Reading time: 3 min

What’s more heartwarming in the wintertime than struggling up close to the fireplace, drinking a cup of hot cocoa while watching your favorite movie? Well, how about going for a run or hike in fresh, mountain snow, or taking a walk on your neighborhood parkway as snowflakes flutter down upon your eyelashes?

While wintery terrain may give you cold feet, it’s all warm and fuzzy when it comes to your heart. And here are six tips to help keep your heart warm this winter.

1. Winterize it

Cold weather can put a large strain on the heart, especially if you aren’t used to it. Cold temperatures cause your blood vessels and arteries to shrink, restricting blood flow and reducing oxygen to the heart. Due to this, your heart has to pump harder to move the blood through the narrowed vessels. When this happens, your blood pressure and heart rate increase.

And as we know, a sudden spike in blood pressure – especially when paired with outdoor exertion, can have scary, even life threatening consequences.

In order to avoid this, make sure that your heart is in good shape before winter by implementing a regular cardiovascular exercise regimen well before the winter months.

2. Dress appropriately

You wouldn’t wear a winter coat, gloves and hat in the middle of summer for the simple reason that it would cause your body to overheat. The same principle applies to wintertime. Shorts and a tank out in the freezing cold would cause your body temperature to plummet.

By dressing appropriately in moisture wicking layers with your head and hands covered, you will be able to last a lot longer out there in the cold, and your heart rate will be less variable.

3. Warm up

Temperature extremes are not good for the cardiovascular system. Both the extremes of heat and cold can cause changes in the body that may have lasting negative effects and could even lead to death.

This is why it is important to warm up before entering the cold so you can to get your heart pumping blood, easing the transition as you acclimate to the weather. Doing so will also lessen the shock to your cardiovascular system.

4. Drink fluids

Drinking plenty of water helps the heart pump blood through the blood vessels to the muscles more easily, according to the American Heart Association. Simply put, if you’re hydrated, your heart won’t need to work as hard.

And while you won’t sweat as much in the cold because your body is keeping water in to keep your body temperature up, rather than using it to cool you off, you still do sweat. Plus, the air that we breathe in the wintertime has less moisture in it, and our lungs need to use the water in our bodies to moisturize it, according to an Dr. Steven T. Devor – Director of Performance Physiology for MIT and OhioHealth.

So, continue to drink your water, and lots of it!

5. Eat heart healthy foods

Along with drinking plenty of water, it is important to eat heart healthy foods like fish, nuts, berries, and green vegetables to make sure that your heart is in tip-top shape as you exercise during the cold, winter months.

6. Know your limits and listen to your body

Exercising outdoors is awesome because you get to experience this time of year the best possible way. However, with extreme temperatures brings risks both to your heart and body. If you begin to shiver, it is time to bring things indoors because this is the first sign of hypothermia.

And there is nothing wrong with exercising in a temperature regulated room. Nothing at all.

Reading time: 2 min

In the mid 1990’s creatine was introduced to the United States full throttle when an estimated 80 percent of Olympic athletes competing in the 1996 Games used it to enhance their performances. Since then, creatine has had both good and bad press. There are those who have sought to ban it as an illegal performance enhancing substance, while many have been proponents of it as a safe and natural product for athletes.

But, who is right? Is creatine safe or should athletes use caution? Moreover, for the purpose of this article, what is its effect on the heart, if any?

First, what is Creatine?

Creatine is a combination of the three amino acids, glycine, arginine, and methionine, and is produced by our own bodies. This same process that occurs in our bodies to produce creatine also happens inside animals we eat, such as herring, salmon, tuna, and beef. This is where we get the supplement that is widely used by athletes today.

What is creatine used for?

When creatine was first discovered in 1832 by French philosopher and scientist, Michel Eugene Chevreul, it sparked many studies. One in particular found that more creatine was present in wild animals vs. domesticated, indicating that there was more creatine produced because wild animals exercised more.

Subsequent tests in humans over the next several decades found that the use of creatine increased muscle mass. It was later concluded that the supplementation of creatine was helpful in treating medical conditions like muscular dystrophy and Parkinson’s. Athletes took notice, and began using it to increase muscle mass to better compete in their chosen sport.

Creatine role is to replenish the body’s reserves of ATP (adenosine tri-phosphate), the muscles’ ultimate energy source for short, explosive bursts of energy. And while recreational use of the supplement has increased over the years, creatine is more beneficial for high-performance athletes who are looking for a competitive edge.

Is it dangerous?

Despite many hoping to find that the use of creatine is harmful, researchers have yet to find anything substantial.This is mainly due to the fact that creatine is considered a food because it is a natural product derived from animals.

While creatine as a supplement alone has not been found to be harmful, when combined with medications, it could potentially damage the liver and kidneys, according to the Mayo Clinic. This is because the creatine in our bodies is filtered through the kidneys, and high levels in the kidneys can be an indicator of potential kidney failure. This is why it is also important to use the supplement only as directed.

The effect of creatine on the heart

There have been some concerns about the use of creatine with some believing there is a link to  increased heart rate and blood pressure. This is due to the fact that the supplement is used primarily to increase the intensity of workouts. However, researchers have found no direct link between creatine use and heart problems, but rather attribute it to athletes overtraining.

How HRV monitoring can help when using creatine

Because creatine will help increase your body’s ability to handle intense workouts, this makes it even more imperative that you track your heart rate variability (HRV) daily to prevent overtraining.

Simply by tracking your HRV you will be able to know when to hit it hard or when taking it easy is best — yes, even when your giant muscles may be telling you otherwise.

Reading time: 5 min
Whether you’re a fitness newcomer or an endurance athlete looking for ways to perform better, gauging your fitness level is crucial. Doing so gives you a starting point from which you can improve, and it can guide your workouts to meet your specific exercise goals. It can also help you identify what types of exercise you excel at and where you need some work. Measuring how fit you are usually involves several different parameters. These include how much muscular strength you have, your body composition and flexibility, how much strain your muscles can endure, and your aerobic capacity. In this guide, we’ll focus on aerobic capacity – a measurement of how much oxygen your body uses during exercise. You’ll learn why it matters, how to measure it, and discover ways to improve it.

What Is Aerobic Capacity?

Aerobic capacity, also known as cardiopulmonary capacity, cardiorespiratory fitness, or VO2 max, is a measurement of your maximum oxygen consumption during physical activity. It’s a reflection of your aerobic power and your body’s ability to keep performing under strenuous activity for longer periods of time. Here’s the science behind it: As you exercise, your lungs draw in oxygen and transfer oxygenated blood to your heart, cells, and muscle groups throughout your body. The oxygen-rich blood pairs with glucose to trigger the production of ATP (adenosine triphosphate) — an organic compound that helps your working muscles contract. This process enables you to run long distances, swim laps, and ride your bike.

Why Aerobic Capacity Matters

Your aerobic capacity is a reflection of your overall health. While maximal oxygen uptake can decrease with age, it can also diminish when you stop exercising regularly or when you get injured. Aerobic capacity is important because it can help you stay healthy and active. In fact, aerobic exercise can help build muscle mass, support skeletal muscle health, and may reduce blood pressure in people with hypertension. Having poor aerobic capacity can also impact your heart health. Research links poor aerobic capacity with a greater risk of heart disease in certain individuals. Studies also show that VO2 max increases with aerobic exercise compared to moderate activity, and both are beneficial to heart health in patients with cardiovascular disease. Measuring your aerobic capacity also allows you to see how well your body performs aerobic or endurance exercises. The more you work on your cardiovascular endurance, the higher your aerobic capacity or maximum oxygen uptake will be. This means you’ll be able to work harder and longer as your aerobic capacity increases.

How to Measure Aerobic Capacity

Doctor oversees an aerobic capacity test
There are two main methods to measure your VO2 max: fitness tests or mathematical estimations. Fitness tests are more accurate since they track your oxygen intake during a specific exercise in a controlled environment. On the other hand, there is a standard equation you can use to get a rough estimate of your aerobic capacity. Here’s how each method works.

Fitness Test

The VO2 max test is usually conducted in an exercise lab and can also be measured at some gyms. During the test, you run on a treadmill or ride a stationary bike while wearing a mask. The mask measures the amount of oxygen you breathe in during the exercise testing. Intensity increases throughout the test until you reach the point of exhaustion. These tests may also monitor your lactate threshold — the point at which your body switches from aerobic to anaerobic processes. Anaerobic exercise occurs when your body needs to use other energy sources besides oxygen — such as lactic acid — to continue performing. If your VO2 max test includes lactate threshold testing, you’ll have blood drawn every few minutes to measure oxygen levels in your blood cells.

VO2 Max Formula

While elite athletes often get VO2 max tests regularly, the tests themselves can be expensive since they’re monitored by a doctor in a laboratory setting. That doesn’t mean you can’t figure out your VO2 max if you’re not an endurance athlete. Fortunately, physiologists have created a formula using factors that typically impact cardiovascular endurance to help estimate your oxygen intake during exercise. Some formulas don’t require any exercise testing while others are based on your performance during aerobic exercise at low intensity and moderate intensity . VO2 max usually decreases with age, but your maximum heart rate and resting heart rate also play a role in your cardiovascular performance. Here are a few formulas you can use to gauge your aerobic capacity.
  • Heart Rate Metrics Formula: VO2 max = 15.3 x (maximum heart rate / resting heart rate)
  • Rockport Walking Fitness Test: VO2 max = 132.853 – (0.0769 x your body weight in lbs) – (0.3877 x your age) + (6.315 if you’re a male or 0 if you’re a female) – (3.2649 x the time it takes you to walk 1 mile briskly) – (0.1565 x your heart rate at the end of the 1-mile walk).
  • Brigham Young University Jog Test
    • Women: 100.5 – (0.1636 x weight in kg) – (1.438 x the time it takes to lightly jog 1 mile) – (0.1928 x heart rate at the end of the jog)
    • Men: 108.844 – (0.1636 x weight in kg) – (1.438 x the time it takes to lightly jog 1 mile) – (0.1928 x heart rate at the end of the jog)
The walking and jogging tests are submaximal field tests. This means you shouldn’t be working at your maximum cardiovascular or respiratory output. The pace should be challenging, but not an all-out intense effort. The run test is ideal for kids and healthy adults while the walking test is a better choice for adults who are out of shape or recovering from injuries.

How to Improve Aerobic Capacity

Aerobic capacity: Cross-country skiers on the trail in Bavaria
The most effective way to boost cardiovascular fitness is to incorporate high-intensity endurance training into your regimen. High-intensity interval training (HIIT) is the ideal option when trying to increase your VO2 max. These exercises are usually preceded by a warmup and consist of intense cardio exercises such as sprints, jump lunges, and calisthenics. Each cardio exercise is followed by a brief rest period. During high-intensity aerobic activity your cardiac output increases as your body demands more oxygen to keep performing. When you repeat these exercises regularly over time, your aerobic capacity will increase. Any type of regular exercise will improve your aerobic capacity. If you can’t do high-intensity exercise or prefer strength-training exercises, start with aerobic activities like walking, swimming, or light jogging instead. You can increase the exercise intensity as your fitness level improves and start incorporating higher intensity exercises into your aerobic training.

Improve Aerobic Capacity With Biostrap

Aerobic fitness is a key metric that can help you reach your fitness goals whether it’s weight loss or conquering an endurance race. When it comes to tracking metrics, there’s no better way to monitor your health than using a wearable tracker like Biostrap. With Biostrap, you can track aerobic metrics including your oxygen saturation levels as well as heart rate variability during each exercise session. You’ll also find useful tips on our blog including how to optimize your cardio routines and hack your fitness. Note:  This article is for informational purposes and is not intended as a substitute for medical advice. Please consult a qualified professional if you require medical attention.
Reading time: 4 min

Amino acids are building blocks for optimum health. Nine of the 20 common amino acids are essential to survival. Without these, our bodies wouldn’t have the energy, focus, and regeneration capabilities we need to survive.

Amino acids are broken into groups based on structure and function. One category of essential amino acids is branched-chain amino acids, also known as BCAA. As the only grouping of amino acids with a particular branching structure, these amino acids are often grouped by their appearance and function.

So what exactly are BCAA amino acids, and what do they do? Here’s what you should know about how branched-chain amino acids work in the body plus the best time to take BCAA foods and supplements to optimize recovery.

What Are Branched-Chain Amino Acids?

 

Amino acids combine to form proteins, which help the body grow and repair. There are three main types of amino acids in the body: essential amino acids, non-essential amino acids, and conditional amino acids. Non-essential amino acids are created by the body, while non-essential amino acids must be obtained from food. Conditional amino acids are those which are only needed when a person’s body isn’t properly creating the non-essential amino acids (for instance, when they’re sick).

Branched-chain amino acids (BCAAs) are a type of essential amino acid characterized by their molecular structure. They have a chain that branches off to one side, which differentiates them from other essential amino acids. BCAAs include leucine, isoleucine, and valine. Comprising between 35 and 40% of all amino acids in the body, leucine, isoleucine, and valine each have unique properties that support different areas of growth and functioning in the body.

Leucine

Leucine is a branched-chain amino acid that has been shown to support the healing of bones and skin. It has also been linked to muscle growth, higher levels of human growth hormones, and increased lean body mass. For this reason, it has been shown to help weight loss. Another benefit — leucine can reduce and control blood sugar levels. This makes it an especially important essential amino acid for people struggling with diabetes or pre-diabetes.

Leucine has also been shown to “activate the anabolic signaling molecule mTORC1 (mammalian target of rapamycin complex 1), as well as other factors involved in protein synthesis,” according to a recent article in the journal, Science. In other words, Leucine is essential for protein synthesis — which is essential for survival.

Isoleucine

Like leucine, isoleucine helps control blood sugar and accelerates the re-growth of lean muscles and other tissues in the body. This makes it essential for highly active people such as weight trainers and bodybuilders. Isoleucine is also believed to assist in the creation of hemoglobin, which is the pigment carrying oxygen in red blood cells.

Isoleucine is said to be most beneficial for people with low blood sugar or diabetes, who need to keep blood sugar (glucose) levels steady when taking medications. That’s because isoleucine can help increase glucose intake into skeletal muscle, which helps balance blood sugar. Isoleucine does this better than leucine and valine. While leucine is thought to be the most powerful branched-chain amino acid for muscle gain, isoleucine can support muscle growth as well.

Valine

Valine supports the proper functioning of the smooth nervous system and the brain. Valine also helps prevent muscle breakdown and ensures proper regulation of the nervous system. Another benefit of valine is appetite suppression.

Metabolism and muscle recovery are also known benefits of this essential branched-chain amino acid. Shown to increase endurance and improve tissue recovery, Valine is most useful for long-distance athletes.

Building Muscle With BCAA Supplements

As mentioned, all three branched-chain amino acids play a vital role in promoting lean muscle mass and optimizing recovery. That’s why many people are turning to BCAA supplements to build muscle, boost weight loss, reduce muscle soreness, and improve overall muscle recovery. Specifically, BCAAs can be taken as a pre-workout supplement to reduce fatigue and improve overall performance.

This was demonstrated in a sports nutrition study on college males during an intense bout of cycling. The men who took BCAA demonstrated higher levels of serotonin — an important chemical that boosts mood and reduces fatigue — helping them maintain an intense workout for a longer period of time. Meanwhile, the men who took the BCAA supplement showed lower levels of creatine kinase and lactate dehydrogenase, both of which signify a breakdown of muscle tissue. This suggests that BCAA supplements like Leucine can help with muscle recovery and muscle gain.

People who want to grow muscle mass and exercise more vigorously without soreness slowing them down may also benefit from BCAA supplements. Additionally, muscle wasting, also known as muscle atrophy (shrinking and weakening of muscle) is another condition that can be improved by amino acids. Muscle wasting is more common among people who are elderly, malnourished, or have illnesses such as cancer.

Best Time to Take BCAA

 

While you don’t need BCAAs at every meal, it is important to take them daily. This ensures you’re getting all the nutrients you need so your body can function at its best. Branched-chain amino acids are most commonly found in protein-rich foods like milk, meat, and eggs. However, many plant-based foods also contain these essential nutrients, so vegans can get everything they need from a plant-based diet. For example, beans, soy, corn, cashews, brown rice, and almonds all are whole foods with amazing benefits, like being high in BCAAs.

The best time to take BCAA depends on your fitness goals. For example, if you’re a bodybuilder or you’re engaging in fasted cardio training (training while fasting), you might take BCAA to prevent extended muscle catabolism. This is when existing muscle tissue is used to repair newly torn tissue. When that’s the case, the best time to take BCAA is in the morning before working out.

In fact, taking BCAA supplements on an empty stomach may boost your energy and give you more endurance to power through your workout at optimum levels. If you’re simply hoping to get enough BCAA in your diet, eat balanced, high-protein meals every day.

It’s also important not to take an excessive dose of amino acids or to take these supplements over a long period of time. This is because certain amino acids can accumulate in the body and lead to imbalances. For example, too much leucine can lead to hypoglycemia or pellagra, which can affect the skin, hair, and intestinal tract. Like any other supplement, all amino acid supplements can be dangerous when taken in excess or at an inconsistent rate.

Improving Recovery With BCAAs

Branched-chain amino acids are essential for the human body to function properly. They aid in muscle recovery, fat loss, post-workout recovery, and reduced muscle damage. All the BCAAs that a normal person needs can be obtained through protein-rich sources, so even vegans can get all the BCAAs they need with a balanced diet. However, people engaging in strenuous muscle building or endurance exercises may benefit from a BCAA supplement, which can slow muscle wasting, reduce delayed onset muscle soreness, and help improve overall energy levels for better workouts.

Reading time: 6 min

Half the people reading this will show it to someone else.

Here’s why. It turns out (spoiler alert!) that a weekly massage is not a luxury, it’s one of the top 7 ways restore parasympathetic balance; in other words to keep your body in healthy homeostasis.

First, it’s important to know how our body is run by the ground control of our nervous system. It looks like this:

  • Central Nervous System (Our brain and spinal column)
    • Peripheral Nervous System (Everything else)
  • Somatic nervous system (How we move on purpose)
  • Autonomic nervous system (Things we do without thinking, like our heartbeat)
  • Sympathetic (‘fight or flight’)
  • Parasympathetic (rest and recovery)

How healthy we are depends on how well-balanced our autonomic nervous system is.

Autonomic Nervous System

Our autonomic nervous system (ANS) controls our involuntary and unconscious body functions. It keeps us alive while we sleep. It helps us breathe when we’re unconscious. It tells our heart how fast to beat and makes sure our muscles have adequate blood/oxygen when we ‘tell’ them to move. It operates without our knowledge or consent, without our lifting a finger to help.

There are 2 branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). They do different things but function as corollaries, not opposites. Our SNS is external facing. It provides the speed, energy and fuel to thwart danger. PSNS is internally-directed. It takes care of the daily business of life: Rest. Digestion. Reproduction (yes, with a boost from our SNS during sex). It’s nicknamed Rest & Digest or Breed & Feed. Two sides of the same coin, that can only be spent together.

Within the ANS, there is a constant calibration between the sympathetic and the parasympathetic systems.

Sympathetic Nervous System (Fight or Flight)

Our body constantly scans our environment, evaluating stimuli. When we sense a threat, our sympathetic nervous system leaps into action to immediately divert resources to the parts of our body needed to fight danger.

The SNS activates our adrenal gland. Our breathing quickens, to bring in more oxygen. Our heart beats faster, to increase blood flow to our muscles. Our pupils dilate (get larger) the better to see our foe.

Digestion slows. Our mouth dries. We don’t need to use the bathroom anymore. We are ready for battle.

Parasympathetic Nervous System (Rest and Recovery)

The parasympathetic nervous system is our default setting when we are not in danger. It lets us conduct the day-to-day business of life. Eating. Sleeping. Recovering. Reproducing.

It is an anabolic process, which builds up needed compounds.

When our PSNS is activated our heart slows. Our breathing calms. Because we don’t need to run, fight or hide, our body sends blood to our organs and away from skeletal muscles. We digest our food. We make hormones. We repair our muscles. We build strength. Our body is in a state of relaxation, and this relaxation breeds recovery. The more time we spend in PSNS the healthier we are.

Hormones and Neurotransmitters

Neurotransmitters help neurons communicate with each other across a synapse. Hormones are secreted by glands. Some compounds can act as either a hormone or a neurotransmitter, and can also they can have opposite effects depending where and why they are excreted.

We have two kinds of muscle tissue. Skeletal muscle (striated muscle) is used for voluntary movement. Smooth muscle is used for involuntary actions like digestion and constriction/dilation of blood vessels.

Our nervous system uses hormones and neurotransmitters to make whatever changes in these muscles it decides we need. The main ones are: adrenaline (increases circulation and breathing), noradrenaline, and acetylcholine (slows heart rate).

Balance

The sympathetic and parasympathetic nervous systems are always operational, but there is a balance between them. One or the other is always more active. The yin and yang pull of these two systems keeps our body in homeostasis, or balance. Together they ensure that we have enough resources, in the right places, at the right time. Running from a tiger, or for a train? Your SNS sends blood to your leg muscles and oxygen to your lungs to propel you along. Kicking back after Sunday dinner to watch a game? Your PSNS will relax your skeletal muscles and send blood to your organs to speed digestion.

Exercise and the parasympathetic nervous system

Tissues need oxygen to survive. Blood brings us oxygen. When we exercise, our muscles need 15 to 25 times more oxygen than when we’re at rest. The cardiorespiratory system makes sure our blood volume is adequate to do so.

When we work out, our SNS is activated, initiating key physiological changes.

  • We sweat to regulate our temperature.
  • Our heart beats faster to bring more oxygen to our muscles.

(The UC Davis Sports Medicine Department advises using a heart rate monitor to gauge effort.)

  • We breathe faster to take in more oxygen. We might even pant.
  • Our liver releases glucose for energy.
  • Our blood pressure increases (more volume).
  • Our blood moves from our organs to our skeletal muscles.

(That’s why we don’t eat before we exercise. Exercise slows digestion. Eating makes your body choose between strength and speed or digestion. A good rule of thumb is to avoid small meals or snacks for an hour before exercise, and to wait 3 to 4 hours after a large meal.)

These changes make sure we are ready for action. But what happens when the SNS is overstimulated?

Negative impact of heightened SNS

Our SNS is designed to help us survive life-threatening emergencies. As a catabolic process, it breaks down tissue and expends energy. If we spend too long in this heightened state of SNS there will be negative consequences.

Our bodies cannot easily differentiate between real and imagined stress. Just the idea of exercise, before we start, triggers an anticipatory heart rate increase. Our bodies are not meant to have a perpetually activated SNS. Chronic stress activates our SNS.

The fight or flight response originated to save our lives, not wash us with adrenalin and dread every time our boss shows up unexpectedly or we watch a scary movie.

We toggle between each system as needed.

If we spend too much time in SNS, we neglect our PSNS and our health suffers. When medical professionals say stress is bad for you, they mean an activated SNS, without a return to SNS, is bad for you. All the negative consequences of stress are really negative consequences of SNS. Think of it as adrenalin poisoning. A little bit can save your life. Too much and you’ll be exhausted, unsettled, with cognitive decline, poor sleep, a compromised immune system, and a body that cannot repair itself.

Exercise without recovery will end in depletion, not strength.

PSNS bolsters recovery

Activating the PSNS promotes recovery and can be measured via heart rate variability. The more time we spend in PSNS the faster we bounces back, repair damage, and gain strength.

Restorative sleep helps. Our autonomic balance during REM is similar to wakefulness. During non-rapid eye movement sleep the balance shifts from SNS to PSNS dominance, bolstering recovery.

How to restore balance

So back to the massage we promised you.

Once we understand the difference between SNS and PSNS we can actively try to stimulate our PSNS. Coach Chrissy Zmijewski recommends activating our PSNS to decrease recovery time after exercise. Here are 7 fixes to restore the balance between your SNS and PSNS.

Reduce Stress

Stress is ubiquitous. Good health depends on removing or reducing whatever stressors we can control, and reduce our reactions to those we can’t.

Meditation

We can’t remove all external stress. Meditation is the best way to decrease our reactivity to stress we can’t control. It teaches us to ignore triggers. It reduces our breathing, slows our heart, and decreases our blood pressure: all signs of PSNS activation. Meditations reduce lactic acid in our muscles, promoting recovery.

Massage

Regular massage has been shown to restore balance between SNS and PSNS. Massage makes us stronger, calmer, and more able to fight infection. By activating the PSNS, massage promotes recovery. It retrains the body to move more readily into PSNS even when we’re stressed.

Breathing

Breathing straddles the peripheral nervous system and the autonomic system. It happens automatically but we can also control it. We can hold our breath for example, but we cannot stop our heart. Slowed breathing is a hallmark of PSNS. But it’s not just a symptom, it’s a signal. Slowing your breathing intentionally tells your SNS that things are okay. This activates the PSNS.

Daily breathing exercises will strengthen your lungs, improve your immune system, and decrease your resting heart rate. Here’s a simple way to activate your PSNS. Inhale for a count of 2. Hold that breathe for a count of 5. Exhale for a count of 7. Repeat.

Yoga

Like meditation, yoga will bring you into PSNS, It also bolsters your ability to decrease SNS activation when you are stressed.

Daily or weekly yoga classes, or even a quick yoga video at home, will improve your strength, flexibility and breathing.

Nutrition

Can what you eat affect your SNS/PSNS balance? Yes. Avoiding stimulants such as caffeine and sugar will facilitate PSNS. An anti-stress diet brings the right mix of protein, minerals and other nutrients to support PSNS.

Exercise

Yes, intense exercise, even the idea of it, stimulates our SNS. But regular aerobic exercise such as light jogging can actually decrease SNS activity and activate our PSNS. The key is moderation and measurement.

Unwelcome sympathy

Our sympathetic nervous system is key to our survival. But like the sympathy of a well-meaning friend, too much can be, well, too much. The more time we spend in PSNS, the healthier and stronger we’ll be. These 7 tips are a great start.

Reading time: 5 min

If you’re looking to get fit, you’ve probably heard about heart rate. The last time you took your heart rate though may have been in grade school as part of your PE class. For others, monitoring heart rate is a daily task that helps them understand the effectiveness of training programs and overall health.

Whether you’re an experienced athlete or someone who’s just looking for more information about heart rate, this guide is here to help. Here, you’ll learn what heart rate is, how to calculate resting heart rate, and how to figure out your target heart rate during exercise. We’ll also give you some tools you can use to improve your health.

What Is a Normal Resting Heart Rate?

Resting heart rate (RHR) is a measure of the number of times your heart beats in one minute when at rest. Even minor to moderate activity such as walking or drinking a cup of coffee can change your heart rate speed. Your medications, hormones, body size, stress and activity level can also lead to changes in resting heart rate. To find your average resting heart rate, it’s best to check first thing in the morning, before you do anything else.

The normal resting heart rate is between 60 to 100 beats per minute (BPM). Medical experts use the term bradycardia for resting heart rates lower than 60 and tachycardia for heart rates above 100 beats per minute.

In general, it’s better to have a lower heart rate than a higher heart rate. That’s because a lower heart rate means your heart doesn’t have to work as hard to keep things operating smoothly. Research also shows a correlation between high heart rate and health conditions including high blood pressure and metabolic syndrome.

Why Does Resting Heart Rate Matter?

 

Resting heart rate is an indicator of overall health. Changes in resting heart rate can be among the first signs of an underlying issue. Having a lower resting heart rate doesn’t necessarily indicate a cause for concern. Elite athletes and people who have a high fitness level tend to have lower resting heart rates. Medications and sleeping patterns can also lead to lower resting heart rates.

In some cases, low heart rates or significant decreases from your normal baseline can be a sign of an underlying problem such as heart disease. Additionally, heart attack, underactive thyroid, and some infections can also cause low resting heart rate.

Your heart rate varies when you’re under stress during strenuous exercise and when you’re just lounging. It’s normal for your heart rate to be higher when you exercise because your heart has to pump oxygenated blood to your organs faster when you’re exerting a lot of energy. Exercise and mood changes can cause an increase in resting heart rate. Think about the last time you were really excited or nervous. The feeling of your heart pounding in your chest is a reflection of an increased heart rate.

When your heart rate is consistently too high, you may have a health problem. Asthma and other breathing conditions can cause an increased resting heart rate. Anemia, heart problems, and medications can also raise heart rate numbers.

Fortunately, it’s easy to measure your resting heart rate so you can stay on top of your health. Read on to find out how to calculate your resting heart rate.

How To Calculate Resting Heart Rate

 

You can check your heart rate by using a wearable tracker or taking your pulse on your wrist or neck. To measure the number of beats using your wrist, place your pointer and middle fingers against the radial artery on the inside of your wrist. This artery is located just below your thumb. You can also check by placing these two fingers against your neck on the carotid artery, which is located just underneath the jaw and next to your windpipe.

You should be able to feel a faint pulsating as your blood pumps through your artery. Set a timer on your phone or stopwatch for 30 seconds and count how many times your heart beats in that time frame. Double that number to get your beats per minute.

It’s important to note that measuring your heart rate using your fingers can be inaccurate, especially if you don’t have a timer to track the 30 seconds. You may also miss a beat here and there, resulting in an inaccurate resting heart rate number.

A wearable tracker or heart rate monitor like Biostrap’s wristband takes the guesswork out of heart rate calculation. These trackers use an infrared or LED light sensor to measure your heart rate. It’s more accurate and the Biostrap tracker includes an app that allows you to manage all of your health information from sleep to heart rate variability.

Heart Rate for Exercise

Now that you know how to calculate your resting heart rate, you can also monitor your target heart rate when exercising. Target heart rate indicates the minimum number of times your heart has to beat in order to conduct cardiovascular activity. According to the American Heart Association and the CDC, the normal target heart rate should be 64% to 76% of your maximum heart rate.

Maximum heart rate is based on age. To find your maximum heart rate, subtract your age from 220. This is known as the Heart Rate Reserve (HRR) method and gives you your target heart rate training zone. For example, say you’re 60 years old. You would subtract 60 from 220 and get 160 beats per minute. Next, you’d take 64% and 76% of 160 to get your target heart rate zone. Your target zone would be between 102 and 121 beats per minute.

These figures are just a guide so don’t panic if your numbers aren’t dead on. If you’re concerned about your resting heart rate or ability to reach your target heart rate during exercise, talk to your doctor. A qualified physician can help you figure out what’s normal and what, if anything, you need to do to stay healthy.

The Best Time To Check Resting and Target Heart Rate

Calculating your heart rate is simple, but there are a few tips that can make it easier or more accurate. It’s a good idea to check your resting heart rate first thing in the morning before taking medication or drinking caffeine, both of which can speed up your heart rate. You can also check your heart rate during physical activity to make sure you’re in your target training zone.

If you want to calculate your resting heart rate, make sure to wait for one to two hours after any physical activity. It can take some time for your heart to return to a normal rate, even after mild exercise. If you forgot to check your resting heart rate before drinking caffeine, try taking it an hour later when the effects subside.

While physical activity can affect your resting heart rate, so can a lack of activity and body position. Don’t take your resting heart rate if you’ve been sitting or standing in one spot for hours. Instead, take a short walk, and then wait one hour before trying to measure your resting heart rate.

Stay Informed and Monitor Your Health

Resting heart rate is a measure of the number of times your heart muscle beats every minute. It’s a good indicator of overall heart health and can be a useful tool for athletes and people who are trying to get in shape. Knowing your resting heart rate and target heart rate range can help you stay fit, get the most out of your exercise program and protect your healthy heart. It can also help you boost exercise intensity so you can target a fat-burning zone and build cardiovascular strength.

If your normal heart rate is too low or high, talk to a doctor and get medical advice. These numbers may be a sign of cardiovascular disease or another underlying health condition.

If you’re interested in more health topics, we’ve got you covered. Check out our blog for more information on important health metrics from oxygen saturation level to sleep tips and more. It’s a great way to stay informed and learn new ways to monitor and manage your health.

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From maintaining a healthy weight to living longer, eating healthy offers many benefits for our long-term wellbeing. The foods we eat also have a major impact on our heart — especially for those who suffer from a high heart rate.

Having a high heart rate is a dangerous condition that can increase a person’s risk for heart attack, stroke, and cardiovascular disease, all while shortening their life expectancy. Here’s what you should know about heart rate, plus the best foods that lower heart rate and improve quality of life.

Why Does Low Heart Rate Matter?

Heart rate fluctuates throughout the day depending on a person’s activity. According to Harvard Health Publishing’s Howard LeWine, M.D., walking around, lying down, and sitting all require different amounts of effort, which will cause the heart to beat at different rates.

Regardless of this change in activity level, a person’s resting heart rate — the number of heart beats per minute at rest — stays consistent over time. For example, a person’s resting heart rate will be consistent each night during sleep, regardless of the activity they engaged in that day.

Heart rate is an important predictor of health. Some people, such as athletes or pregnant women, are expected to have a lower or higher heart rate, respectively. Age and hormonal fluctuations also affect how fast a person’s heart beats.

When an average person’s resting heart rate falls outside the normal range — 60-90 beats per minute — it can signify a serious health problem. Having a high heart rate is called tachycardia, and there are many types of increased heart rates.

Perhaps the most common type of tachycardia is atrial fibrillation, which is caused by irregular electrical impulses in the upper heart chambers. Atrial fibrillation is a sign of weak contractions in the upper chamber of the heart (the atria). Atrial flutter is an associated condition marked by a rapidly beating atria and a normal heart rate.

A high heart rate doesn’t always cause symptoms, and seeking professional medical advice is sometimes the only way to diagnose this condition properly. When symptoms are present, they can include shortness of breath, lightheadedness, rapid pulse, heart palpitations, chest pain, and fainting. If you’re unable to exercise because of these factors, it’s a sign that it’s time to take control of your heart health. So what happens if you don’t intervene?

The Role of Heart Rate in Heart Attack and Disease

 

Having a high heart rate can affect everyday life by contributing to daytime fatigue, low fitness levels, and obesity. Yet it’s particularly dangerous because it puts people at higher risk for developing heart disease or suffering from additional cardiovascular disorders.

A high heart rate is linked to health issues like heart disease, stroke, and cardiac arrest. Research also shows that having an above-normal heart rate increases a person’s chance of death, regardless of whether they’re physically fit or generally deemed healthy. This study, which measured 3,000 middle-aged men, found that for every additional 10-22 beats per minute, a man’s chance of death increased by 16%.

Causes of High Heart Rate

The most common causes of high heart rate are hypertension (high blood pressure) and coronary artery disease — both of which can be controlled by lifestyle factors. In particular, things like chronic stress and excessive use of caffeine are all modern factors that contribute to high heart rate.

Additional risk factors that elevate resting heart rate include excessive alcohol consumption and alcoholism, taking certain medications, smoking cigarettes, and taking recreational drugs. High blood pressure is another common cause of high heart rate.

Medical professionals have understood the correlation between lifestyle and heart health for quite some time, but recent research shows that high heart rate can be caused by a variety of genetic factors.

For example, a heart study led by cardiologist Pim van der Harst found 64 gene locations that influence heart rate, suggesting that genes and gene location influence both heart rate and life expectancy more than previously thought. Congenital heart defects, which can be caused at birth or after heart surgery, can also cause the heart to beat irregularly.

Diet plays a significant role in high heart rate because the foods we eat affect our blood pressure. Alcohol and stimulants are especially hard on the heart because they cause dehydration and are considered toxic to the body. This means the heart has to work harder to remove them — leading to an increase in heart rate.

Foods high in fat and sugar also cause an increased heart rate, primarily because they contribute to being overweight or obese, which places more pressure on the heart.

Foods That Lower Heart Rate

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Despite the role of chronic and genetic factors in heart health, changing one’s diet to include more healthy foods is the quickest and most effective way a person can achieve a lower heart rate and improve overall healthLowering your heart rate can reduce the risk of heart disease, heart attack, and stroke while helping lower blood pressure. Here are the nutrient-dense foods that lower heart rate, reduce heart disease, and boost longevity.

Whole Grains

Whole grains are an important element of a heart healthy diet and offer many health benefits. A diet high in whole grains has been shown to reduce cholesterol, blood pressure, and blood sugar levels.

Whole grains have also been shown to reduce the risk of stroke, type 2 diabetes, and heart disease — all of which are associated with high heart rate. Whole grains also work to keep you full for longer. This can reduce the risk of overeating to help an overweight person lose extra pounds and reduce excess strain on the heart.

Simple, heart-healthy, whole-grain swaps and substitutes include choosing whole wheat flour instead of refined white flour, oatmeal, bulgur, whole wheat pasta, and barley. They are all examples of healthy whole grains to incorporate into your diet.

Green Vegetables, Leafy Greens, and Fruit

Green vegetables and leafy greens are especially beneficial for cardiovascular health because they contain vitamin K1. Eating high amounts of vitamin K1 can protect against high heart rate and an enlarged heart. It has also been shown to reduce high cholesterol. Fruits and vegetables are low-fat foods that contain fiber, which is known to lower both cholesterol and high blood pressure.

One study found that eating 10 servings of fruit and vegetables a day can lower your risk of cardiovascular disease by 28% while reducing the risk of premature death by 31%. Aside from leafy greens, apples, pears, citrus fruits, cruciferous vegetables, green beans, and peppers were shown to offer the best heart benefits.

Blueberries, which are high in anthocyanins (the phytochemicals that give blueberries their color) have also been shown to improve heart health. Specifically, blueberries have been shown to decrease blood pressure, improve blood vessel function, and reduce the risk of cardiovascular disease.

Omega-3 Fatty Acids

 

Omega-3s are healthy fats found in a variety of plant foods and fish. Omega-3 fatty acids are one of the best foods to lower heart rate and reduce the risk of cardiac arrest. There are three main types of Omega-3s. These include alpha-linolenic acid (ALA), which is found in plant oils, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are found in fish like salmon, mackerel, and tuna.

Omega-3s keep heart rate low while reducing the risk of irregular heartbeat, slowing down the buildup of artery plaque, and lowering blood pressure. Aside from eating fish, plant foods that contain essential fatty acids include ground flaxseeds, chia seeds, soybeans, and tofu. Walnuts also contain high amounts of Omega-3s, with almonds, macadamia nuts, hazelnuts, and pecans coming in second. Avocado, olives, and olive oil are also known to be high in ALA omega-3s.

Eating for a Healthy Heart

Heart rate plays a vital role in a person’s overall health. While athletes, pregnant women, and people with congenital heart defects are expected to have an abnormal heart rate, people outside of these categories should have a resting heart rate between 60-90 beats per minute. Having a heart rate above this range can put a person at risk for a variety of life-threatening diseases and conditions, including heart disease, heart failure, and heart attack.

Fortunately, eating healthier foods is one of the most effective ways a person can reduce their risk of disease and extend their life expectancy. Leafy greens, fruits, whole grains, and items rich in Omega-3s are all examples of foods that lower heart rate and improve overall quality of life.

Reading time: 5 min

Fatigue happens after all difficult exercises. Running a mile gets harder after you’ve already run two. Powerlifting becomes more challenging after multiple reps. Recognizing this fatigue is how we continue pushing ourselves to run further distances and lift heavier weights, growing faster and stronger with every workout.

However, consistently overtraining to the point of exhaustion can cause the brain to become chronically tired. Known as central nervous system (CNS) fatigue, this condition is marked by decreased functioning in the part of the brain responsible for voluntary movement.

While some people debate what causes it, many athletes and active individuals have struggled with the long-term side effects of CNS fatigue. Read on to learn what CNS fatigue is, how to spot the symptoms, and when it’s time to step back and recover.

Understanding the Central Nervous System

Most mental and bodily functions are controlled by the central nervous system (CNS), which is comprised of the brain and spinal cord. The brain interprets everything we see, hear, feel, smell, and taste. The spinal cord is responsible for sending messages about these experiences into the body to elicit a reaction. Speech, memory, movement, and general awareness are all a direct result of a properly functioning nervous system.

The CNS also enables us to engage in physical activity — it’s what helps us run, squat, and lift on command. Specifically, the motor cortex is the area of the brain responsible for helping us plan and execute voluntary movements. Located in the brain’s frontal lobe, the motor cortex is divided into multiple sections that govern different movements and responses.

One important area of the motor cortex is the primary motor cortex, which helps us control different parts of the body on queue. The primary motor cortex helps us learn new athletic skills and complete them faster and more efficiently through repetition.

Central Nervous System Fatigue

The brain and spinal cord are designed to give us freedom of movement, but chronic overtraining can fatigue the central nervous system to the point of inefficiency. This is called central nervous system fatigue, or CNS fatigue.

Extending oneself during workouts is one of the leading causes of CNS fatigue, though it can also be caused by poor sleep and nutrition. CNS fatigue is thought to be most common among weight lifting and strength training athletes, but it can happen to anyone engaging in high-intensity exercise. Plus, everyone has a different work capacity, meaning that some people may be able to endure more strenuous exercise before experiencing CNS fatigue.

Overtraining and CNS fatigue are sometimes put into the same category, but one is more serious than the other. Overtraining is a common side effect of trying a new and rigorous exercise routine, and it can usually be overcome with a few days of adequate rest and nutrition. In contrast, CNS fatigue results from chronic muscle fatigue and is more difficult to overcome.

What Causes CNS Fatigue?

According to the late Olympic coach Charlie Francis, CNS fatigue is caused when high-intensity work occurs too often during training or when high-intensity exercise persists even in the presence of fatigue from a previous workout. When the motor neurons responsible for voluntary movement are forced to fire very quickly and very often, they get tired.

This results in CNS fatigue — where a person’s neurons don’t fire as quickly as they should. When the brain doesn’t send messages to the body to move quickly, a person isn’t able to exercise at the same rate as before.

CNS fatigue also inhibits muscle regrowth, which reduces exercise performance. For example, lifters may start to notice that they’re not building muscle as quickly as before or that their training program has become less effective.

Unlike peripheral fatigue, the normal muscle tiredness that occurs after lactic acid buildup from a workout, chronic CNS fatigue causes persistent symptoms that interfere with a normal workout regimen.

One of the first symptoms of CNS fatigue is irritability and emotional changes. It also disrupts sleep patterns and can cause either food cravings or loss of appetite, all of which can exacerbate a heightened emotional state.

Another core sign of CNS fatigue is a weakened immune system. If you find yourself feeling sluggish throughout the day and you’re getting sick more often than normal, it could be a sign your body is struggling to fight off everyday pathogens.

Overcoming CNS Fatigue

Rest is the first and most important way to overcome CNS fatigue. Sleep helps your body recover and promotes muscle growth, which ensures your workouts remain effective. In addition to getting enough sleep each night, you’ll also want to schedule adequate downtime between workout sessions.

Workouts that require more muscle activation, such as heavy weight lifting or spinning, should be balanced with more rest, and you should have a post-workout recovery plan that includes proper nutrition.

Similarly, meditation can help reduce the mental and bodily stress associated with CNS fatigue. Whether you’re already experiencing fatigue or you’re working to prevent it, a regular meditation practice can clear your mind and help you get back in the game.

Change Your Workouts

Your workouts are also going to need to change if you want to overcome CNS fatigue. Studies show that muscular fatigue occurs more with endurance exercises like long-distance running or bicycling.

Rather than decreasing your training volume and working out less, you can simply change what you’re doing so that you’re still increasing your heart rate without enduring prolonged exercise.

Coach and bodybuilder Jason Ferruggia suggests using straps and deadlift variations when lifting weights. This reduces the need to grip the bars tightly, which can ease CNS stress. Similarly, switching to fat bars when lifting weights can reduce stress on the nervous system.

Training sessions that alternate muscle groups on different days are a great place to start. You may also consider turning to low-intensity exercises like swimming or cycling for short periods.

Alter Your Lifestyle

Many people who suffer from CNS fatigue also have busy, stressful lives. Learning to say no to tasks, events, and outings that don’t serve you can help you create more space for rest.

Being more mindful about what you do and how you spend your time can retrain the brain to act normally, rather than overfiring. Reducing daily stress is an important aspect of overcoming CNS fatigue, as it’s a result of chronic stress on the mind and body.

Additionally, neurotransmitter imbalances are associated with CNS fatigue. Changing your diet can help you rebalance serotonin and dopamine to get back to feeling your best. In addition to eating a diet low in refined sugars and processed foods, you can boost your body’s stress response by supplementing with fish oil, curcumin (found in turmeric), glutamine, and amino acids like tyrosine.

Strengthen the Motor Cortex

Strengthening the brain (and the motor cortex in particular) can also help you overcome CNS fatigue so you can return to your normal workouts. Repeating the same low-intensity workouts on alternating days can retrain the brain to work out without getting excessively fatigued. It can also help you create muscle memory in new areas of the body.

Overcoming CNS Fatigue for Health and Prosperity

Fatigue is a normal side effect of exercise. But if you’re feeling chronically irritable, tired, and like you can’t exercise to your fullest capacity, you may be experiencing CNS fatigue.

CNS fatigue is when the motor neurons in the brain don’t function as efficiently as they should, which takes a major toll on your ability to perform at your best. Fortunately, getting enough rest and taking care of your body can help you overcome this challenging, yet common condition so you can achieve optimal health.

 

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Aerobic and anaerobic exercises are different ways of working out that both provide tremendous health benefits. The term aerobic means ‘with oxygen’, and the term anaerobic means ‘without oxygen’. This refers to the way the body uses energy to perform the exercises.

While these forms of physical activity impact the body in different ways, they both play an important role in overall health. Learning about the differences can help you take your fitness and health to a higher level. 

What is Anaerobic Exercise?

Anaerobic exercise refers to short, quick, high-intensity exercises when the body does not use oxygen as an energy source. Instead, these exercises  activate fast-twitch muscle fibers, like heavy weightlifting or sprinting, when oxygen demand surpasses oxygen supply. 

When you work out, your heart rate increases and your body works to pump more oxygen to muscles. During anaerobic activity, this oxygen isn’t enough to supply your body with the energy it needs to continue performing the activity. Instead, the body uses energy in the form of glucose that is readily available inside of the muscles.

Accessing this energy involves a process called glycolysis, when glucose is converted into adenosine triphosphate (ATP) for energy. This can provide energy for high-intensity activities that last 10-15 seconds.

The second energy system is the lactic acid system, and it works in sequence with the ATP system. As your body produces ATP, it creates pyruvic acid, which is then broken down into lactic acid and lactate. In the liver, these compounds are converted to glucose, called gluconeogenesis, which the body uses as energy. This energy can be used to power high-intensity physical exertion for about 2 minutes. As lactic acid and lactate build up in your muscles, you begin to feel fatigued. This is what triggers the need to take a break during these high-intensity, short-duration workouts. With regular anaerobic exercise, the body will be able to tolerate and eliminate lactic acid more efficiently, allowing you to push further without feeling  fatigued too quickly. 

What is Aerobic Exercise?

Aerobic exercise is activity that uses large muscle groups and can be maintained with ease. These activities use oxygen to generate energy and maintain continuous movements of the large muscle groups. The muscle groups used during these activities use aerobic metabolism to extract fuel from fatty acids, carbohydrates, and amino acids. When you do aerobic activities, your body uses slow-twitch muscle fibers which can maintain contractions without quickly fatiguing. 

Aerobic exercise is anything that requires a steady amount of energy, which can be sustained over a long period of time. Activities like, walking, long-distance running, cycling, cross country, skiing, and swimming are aerobic exercises.

What are the benefits?

Anaerobic workouts are great for building muscle mass and improving power. Whereas aerobic exercises improve endurance and strengthen the cardiovascular system. While anaerobic and aerobic workouts are different, they’re both equally important to your overall health and a well-rounded exercise regimen. 

Anaerobic and aerobic exercises share several mental and physical health benefits including:

– Protect against bone loss
– Weight management
– Improve mood
– Boost energy
– Improve heart health
– Support healthy metabolism
– Improve self-esteem
– Bolster the immune system

It is clear that both types of exercises have a place in a well-balanced fitness routine. Incorporating both anaerobic and aerobic activity allows the body to build strength and endurance while unlocking all of the health benefits listed above. 

Get Moving With Biostrap

Whether it’s anaerobic exercise or aerobic exercise, Biostrap makes it easy to track all of your fitness biometrics and ensures you’re getting the most out of each and every workout. Our collection of health tracking devices offer insights into your resting heart rate, active heart rate, heart rate variability, respiration rate and oxygen saturation levels, along with sleep and recovery parameters. Paired with the Biostrap app, we make it easy to monitor your workouts and create exercise routines that fit your needs.

Our activity classification tool also makes it incredibly easy to get detailed data from every workout. You can classify your favorite cardio activities and strength training exercises. This helps give you insights into rep consistency, the duration of your exercise, and how many calories you’ve burned.

The wristband and Activity Pod work seamlessly to provide a 12-axis motion capture to monitor everything from hand movements to velocity. Adding one of our external heart rate monitors, you can even track heart rate progression in real-time and monitor specific exercise zones, such as warm-up, fat burn, cardio, hardcore training, and maximum effort. By tracking your every move, you’ll be able to push yourself to achieve new fitness goals and better health. 

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Whether you are training for a marathon, hiking up a mountain, or climbing the stairs to your bedroom, there is one thing you will need for all three activities: cardiovascular endurance. 

Understanding cardiovascular endurance is the first step to being able to improve it. We’ll touch on what cardiovascular endurance is, how to measure it and how to improve it. 

What Is Cardiovascular Endurance?

Cardiovascular endurance is a measure of how well you can perform large-muscle, dynamic exercises at  moderate to high intensity for an extended period of time (typically over 20 to 30 minutes). It is a measurement of your body’s ability to remove carbon dioxide and pump oxygen-rich blood to your organs. This makes cardiovascular endurance a direct indicator of heart function, lung capacity, and muscle function. If you have high cardiovascular endurance, you’ll be able to perform intense exercises and workouts longer than someone who has low cardiovascular endurance.

Here’s the science behind it: When you inhale, your body draws in oxygen from the outside world, filling your lungs. Some of this oxygen helps you continue breathing while other oxygen atoms are transferred into the bloodstream. This oxygen-rich blood then travels to the heart where it’s pumped out to your muscles, cells, and organs through the circulatory system.

When you engage in strenuous physical activity, your muscles need more oxygen than when you’re resting. This means your cardiovascular system works harder than normal to move oxygenated blood to your working muscles. If you have poor cardiovascular endurance, you won’t get enough oxygen to your muscles and you may feel light-headed or start to experience fatigue.

How To Measure Cardiovascular Endurance

Cardiovascular endurance involves measuring the amount of oxygen your body uses during intense exercise. There are two metrics used to provide insight into the health of your cardiorespiratory system: METs and VO2 Max. 

METs

Metabolic equivalent (MET) is a ratio of the amount of oxygen consumed while at rest compared to the amount of energy expended when you’re exercising. One MET is the calculation of how much energy, measured in calories, you expend while at rest. The number of METs you use up during exercise indicates how much harder you are working. These MET scores can be derived from a stress test using a treadmill or stationary bike, usually performed at a medical facility or sports clinic. 

VO2 Max

The second test measures your VO2 Max, which is also known as maximal oxygen uptake. This test measures the maximum amount of oxygen your body consumes during sustained and exhaustive exercise. The test is performed while an individual performs graded maximal exercise on a treadmill or a bike, while wearing a mask measuring oxygen consumption as well as a  heart rate monitor. VO2 Max tests are generally expensive and performed by a clinician or exercise physiologist. 

Why Cardiovascular Endurance Matters

Having high cardiovascular endurance means you can perform strenuous activities for longer periods of time. This is important not just in the gym, but for performing daily tasks in everyday life. Increasing cardiovascular endurance has a positive impact on overall health and fitness. Focusing on improving cardiovascular endurance can also be beneficial to maintaining a healthy body composition, due to performing higher levels of aerobic activity. Additionally, you may experience improved sleep, decreased stress and improved immune system.

The good news is that cardiovascular endurance can be improved with small changes to daily movement and exercise. 

How To Improve Cardiovascular Endurance

The best way to improve your endurance levels is to increase the volume and intensity of your exercise. While all types of exercise can improve endurance, some are more effective than others.

Aerobic activity is particularly useful as it involves sustaining high output for extended periods of time. This can help increase your heart’s stroke volume, so your heart will become more efficient in pumping oxygenated blood to muscles with every beat. It may also help improve lung capacity, meaning you’ll increase your VO2 max over time.

Aerobic exercise is different from anaerobic exercises, which involve short bursts of energy and include activities like weight training programs, high-intensity interval training (HIIT), and sprints. Endurance exercises like jump rope, running, swimming, dancing, and mountain biking are all great aerobic activities.

You can also play sports including: soccer, hockey and basketball. Basically, you’re looking for exercises that require you to maintain moderate activity levels for long periods of time. This will help train your body to use oxygen more efficiently and improve your cardiovascular endurance.

Anaerobic exercise programs on the other hand are also important as they can strengthen your ability to perform at peak levels. This will help increase your VO2 max, and over time, you’ll be able to perform at a higher intensity without feeling fatigued as quickly. Incorporate higher intensity exercises such as calisthenics, heavy weightlifting, and resistance training to improve your cardiovascular endurance.

How Biostrap Can Help

When it comes to health and performance, Biostrap is the ultimate tool. Our devices make it easy to track health metrics and give you insights into your overall health and performance. Whether you’re looking to maximize your endurance training or focus on strength training and working certain muscle groups, our devices make it easy to reach your goals. 

Our Biostrap Recover Set is perfect to monitor your health while you’re asleep. Besides various sleep parameters, it measures your resting heart rate, oxygen saturation, heart rate variability, and respiratory rate. To accurately track your active heart rate, HRV, caloric expenditure and heart rate progression, make sure to grab one of our external heart rate monitors — armband or chest strap.

With the Biostrap Active Set, you can track everything from rep consistency and caloric burn to exercise duration and heart rate progression, so you can quantify and work toward improving your cardiovascular endurance!

Reading time: 5 min

Most mammals are polyphasic sleepers, meaning that sleep is completed in two or more periods in a 24-hour cycle. Cats, dogs, bears, mice, and most other mammals, either domesticated or wild, take naps throughout the day. In contrast, modern human civilization is based on a monophasic sleep schedule, meaning we sleep only once per day.

While this may be optimal for working productively in a technology-based world, it may be making us more sleep-deprived, suggests The National Sleep Foundation. They also point out that monophasic sleep may not be natural for humans, especially judging by the behavior of other species.

Instead, we might need a polyphasic sleep schedule (i.e. lots of naps). But what are the benefits of napping, and what does it mean to nap well? Here’s a guide to mastering the art of napping — plus how it can help you in mind and body.

Why Does Napping Matter?

Whether or not you’re a person who naps, it’s important to understand how naps influence our mental and physical health. Since naps increase our daily sleep time, they help enhance the positive impacts of sleep on our wellbeing.

This was demonstrated in a napping study at Weill Cornell Medical College where participants were asked to start a daily nap routine, napping for either 45 minutes or two hours for one month. Regardless of nap length, all participants in the study increased their daily sleep time and their nighttime sleep cycle wasn’t disrupted.

These naps also helped participants sleep better for longer. “Napping increased the time spent in slow-wave and rapid-eye-movement (REM) sleep, which are thought to play important roles in restoring the body and brain,” said the study’s authors.

Slow-wave sleep, or deep sleep, is the last stage of non-REM sleep. As the deepest stage of sleep, this part of the sleep cycle is critical for restoring energy levels and promoting cell regeneration. This stage of the sleep cycle also helps boost the immune system, increase blood supply to the muscles, and promote the growth and repair of muscle tissue. Deep sleep’s ability to repair the physical body helps people recover more quickly from physical activity while reducing daytime tiredness.

Sleep and Cognitive Function

The effects of deep sleep on your brain and mental health are equally important. For example, deep sleep is when your body processes the information encountered each day and makes sense of it. This is the process by which memory is created — without deep sleep, we won’t be able to effectively remember the things we’ve learned each day.

This is also why increasing the hours of sleep you get each day is so important for overall cognitive functioning. Chronic lack of deep sleep has been associated with mental deterioration, including cognitive decline, memory loss, and Alzheimer’s.

Additionally, napping decreases the irritability associated with fatigue, helping to improve mood and alertness while promoting relaxation. Napping can be especially important for seniors, as it boosts reaction time — an essential cognitive function that reduces fall-related injury.

Think about it: We’re more prone to getting into accidents when we’re sleep-deprived because we can’t react as quickly. Regular napping can keep us energized, alert, and most of all, safe.

Precautions for Napping

As with any new activity or behavior change, it’s important to know any potential precautions before getting started. While napping is almost always a good idea, it is possible to oversleep under some circumstances.

For example, people who struggle with insomnia may want to sleep during the day for long periods to make up for a lack of sleep during the night — but this can only perpetuate the problem.

Sleeping for too long during the day can disrupt your sleep and create a shift-worker schedule where your body wants to be awake at night and sleep during the day, which also throws off your natural circadian rhythm.

Sleep inertia is another thing to keep in mind. Characterized by feelings of tiredness and grogginess after waking, sleep inertia is when you’re still mentally in a sleep state after waking up. It’s caused by the prefrontal cortex — responsible for decision making and self-control — which sometimes requires additional time to catch up with the waking body. Sleep inertia can impair concentration and make it hard for a person to function normally after taking a nap, which can disrupt daily activities.

Best Time to Nap

If you’re considering adding napping to your daily routine, you’re probably wondering when to nap. When you nap matters because napping too late in the day can make it difficult to fall asleep.

While it’s best not to nap after 5 p.m. as a general rule, some people who are more sensitive to sleep disruptions may want to finish a nap by 4 p.m. to get a restful night’s sleep. Moreover, the National Sleep Foundation suggests taking an afternoon nap between 2 and 3 p.m., especially if you adhere to a standard eating schedule and eat lunch around noon or 1 p.m.

“That’s because you’ve already eaten lunch and your blood sugar and energy levels will naturally start to dip. In fact, your body clock is often programmed to make you feel a little sleepy in the middle of the afternoon,” the National Sleep Foundation explains.

How Long Should a Nap Be?

Napping is important for mental and physical health — especially when napping is approached mindfully. You might decide that you want to nap more often if you’re feeling uncharacteristically tired during the day, or you may simply want to add it to your routine.

But how long is the ideal nap? While the exact amount of time you need for a nap depends on age, physical activity level, and overall health, here’s a look at the different types of naps and their benefits.

Short Naps

Short naps, or power naps, are only 10-30 minutes long. They offer a quick burst of energy without taking too much time out of your day, and they don’t offer much time in deep sleep — thereby preventing sleep inertia and related grogginess. While a half-hour nap will likely offer more benefits than a 2-minute nap, any amount of rest helps make you more energized and resilient against the challenges of the day.

Long Naps

If you’re looking for a nap with more gusto, a 90-minute nap may be the best choice. While a longer nap increases the chances of waking up groggy, it also increases the opportunity to go through more stages of the sleep cycle and receive more of the benefits of sleep (the entire sleep cycle usually takes 90–110 minutes).

Long naps can also release compounds in the brain that make a person more tired, which — in contrast to the belief that napping disrupts nighttime sleep — improves sleep at night.

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More Tips for Rest and Rejuvenation

If you’re not sure about napping or you’re entirely new to the process, you might start with a short afternoon meditation. This gives your body and mind a rest and can produce healthy brain waves similar to the ones achieved in light sleep. You might also take a look at your diet — avoiding caffeine late in the day can ensure you squeeze in both a nap and a full night of sleep without disruption.

If you’re taking sleep medication or even a natural sleep aid like melatonin, you may want to talk to your doctor about stopping the medication before adding naps into your routine.

After all, the restful and healing nature of naps may negate the need for sleep medicine entirely, but only you and your doctor will know if it works for you. Lastly, measuring your sleep efficiency with a sleep tracker can help you gain a better picture of how napping improves your energy levels and supports your evening rest.

Napping to Improve Mind and Body

Napping is a natural mammalian function that has immense benefits for both mind and body. In addition to making you more rested physically, napping helps boost memory and improve resiliency against life’s challenges by reducing stress and irritability.

Napping often can also improve our ability to sleep better at night — as long as we’re mindful about when and how long we sleep. If you’re fatigued daily or you’re looking for a way to boost memory and energy, napping could be an effective way to improve your quality of life.

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We all have days where getting out of bed feels impossible. Whether you were up too late having fun or it’s simply the weekend, sleeping in from time to time is both natural and normal.

For some people, however, waking up early is a constant chore that never seems to get better. Failing to get a good night’s sleep and being unable to wake up early can be major burdens on everyday life, making it harder to be productive and attend early morning engagements on time.

The good news is that this struggle can be rectified. By setting routines and adopting healthy lifestyle habits, you can get on your way to jumping out of bed when the alarm strikes six. Even if you’re a self-proclaimed night owl, here’s how to wake up easier and learn to love your mornings.

Why Waking Up Is Hard

We’ve all experienced feeling sluggish, tired, and unmotivated in the morning. Nearly half of Americans said that poor sleep affects their daily life, according to a study by The National Sleep Foundation. Of those surveyed, 20% also said they didn’t wake up feeling refreshed the next day, and 25% rated their sleep quality as poor.

With data like that, it’s no surprise that so many people struggle to wake up in the morning. But what if you make an effort to go to bed at a decent hour and maintain a healthy, active lifestyle — and still struggle to sleep well and wake up with energy? Several sleep disorders could be to blame.

Sleep Disorders That Make Waking Up Hard

Certain sleep disorders and conditions can exacerbate the grogginess you feel upon waking up. For example, sleep apnea is a common sleep condition characterized by a partial or complete blockage of the throat.

Sleep apnea is when a person’s breathing involuntarily stops during sleep. Loud snoring is the most common symptom of sleep apnea, but it can also cause a person to wake up gasping for air or with a dry mouth or headache.

Struggling to fall asleep at a normal bedtime or having insomnia also makes it hard to wake up early. Waking up throughout the night, waking up too early, and suffering from daytime tiredness, irritability, and lack of mental stamina are all signs of insomnia. This sleep disorder is considered chronic when experienced for three months straight.

Sleep inertia is another common reason why you might struggle with grogginess and brain fog as you start your day. Though not a sleep disorder, sleep inertia is typically caused by being abruptly awoken either by an alarm clock or another force.

According to neurologist and sleep medicine specialist Dr. Brandon Peters, “This phenomenon leads to sleepiness and cognitive and psychomotor impairment that can occur immediately after awakening.” Sleep deprivation and waking earlier than normal can disrupt slow-wave, or deep sleep, to trigger sleep inertia.

Circadian Rhythm Disruptions

Changes to your circadian rhythm may also be to blame for poor sleep. Responsible for your sleep-wake cycle, your circadian rhythm regulates when you feel sleepy, when you wake up, and how much energy you have during daylight hours.

Circadian rhythms are primarily influenced by light. The absence of sunlight after sunset is what triggers the circadian rhythm to release the hormone melatonin in the brain, which makes us feel tired so we can prepare for a good night’s rest.

Your circadian rhythm can be disrupted by a variety of sleep disorders, including delayed sleep disorder. This disorder, most common in teenagers, is when someone’s internal clock prevents them from going to sleep at a normal hour. As a result, they tend to fall asleep between 2 and 6 a.m., making it hard to wake before the rest of the world has started their day.

Your body’s natural sleep cycle can also be negatively impacted by lifestyle factors, such as working late nights and sleeping through the day. Shift work asks a person’s circadian rhythm to work in reverse and ignore the release of melatonin at night. This can make it harder for a shift worker to get the sleep they need during the daytime, making them chronically tired from day to day.

Additional factors that can disrupt a person’s circadian rhythm include frequently staying up late, having an inconsistent sleep schedule throughout the week, consuming high amounts of alcohol, and experiencing jet lag. Suffering from anxiety and ADHD can also affect a person’s ability to sleep well.

How to Wake Up Easier

Whether you struggle from a sleep disorder like sleep apnea or you’re simply prone to late-night Netflix binges, here are a few lifestyle changes that can make waking up more pleasant.

Clarify Your Motivation

If you’re reading this article, it’s likely you have a reason why you want to get up earlier. Do you want to exercise before work? Do you want to have breakfast with your family?

Getting clear on why you want to wake up earlier can make the change stick. A healthy living expert with a master’s degree in public health, Michelle Segar suggests telling loved ones about the change you’re willing to make. Having an early morning accountability partner can be just the motivation you need to stop hitting snooze and get better quality sleep.

Create a Consistent Bedtime Routine

First and foremost, creating a consistent bedtime routine is essential for rising with gusto. If you go to bed at 1 a.m. one night and 8 p.m. the next because you’re so tired, your brain won’t have time to adjust to consistent sleep patterns. One way to help yourself fall asleep earlier at a consistent time is to set a boundary for your devices.

Since the blue light from smartphones and tablets can mimic the sun and disrupt your circadian rhythm, it’s best to limit their use after sundown. Sticking to this schedule on the weekends can also help you maintain consistency in your sleep-wake schedule to get your biological clock back on track.

Create a Consistent Morning Routine

A morning routine is something almost all early risers have in common. Some people use their time to meditate, exercise, or journal. Other people use it to pour a cup of coffee and read — as it might be their only moment of solitude in the day. Whatever you decide, make sure you’re exposed to ample sunlight. This will keep your circadian rhythms in check for better sleep that evening.

Try the R.I.S.E. U.P. Method

The R.I.S.E. U.P. Method is especially helpful for people who suffer from sleep inertia, but anyone who dislikes mornings can benefit from adopting at least some of these principles. Pioneered by Dr. Harvey of the Golden Bear Sleep Research Center, this technique helps you feel more alert and energized after waking up. This acronym stands for:

Refrain from snoozing
Increase activity for the first hour
Shower or wash face
Expose yourself to sunlight
Upbeat music
Phone a friend

Including even a few of these elements in your morning may be the trick to help you reshape your wake-up routine. Plus, a number of these elements help reinforce other early-riser tips (such as phoning a friend, who can also be your accountability partner).

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Track Your Sleep

Tracking your sleep can help motivate you to stick to your morning and night routines, especially when you start seeing that a consistent sleep schedule may have a positive impact on your sleep, recovery, performance and overall well-being. With the Biostrap Recover Set, you can gain access to valuable insights into your sleep and nocturnal biometrics. And, when you start monitoring trends over time (week, month, year), you’ll see the effects your lifestyle choices have on your physiology long term.

Curious to find out what the best time for you to go to bed and wake up is? Biostrap’s advanced sleep analysis feature, called Sleep Lab, provides you exactly that, and more.

Wake Up Easier and Become a Morning Person

If you’re wondering how to wake up easier, you’re not alone. Millions of people suffer from sleep disorders and lifestyle factors that make it harder to fall asleep, get enough sleep, and maintain a consistent wake-up time.

Fortunately, changing your lifestyle to adopt a morning and evening routine can ensure that you readjust your body clock and create better sleep habits. So what are you waiting for? A more energized and productive morning awaits!

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Why Am I Always Tired?

Occasional tiredness is normal, especially after a schedule change or a late night. But if you’re feeling tired all the time, you may be severely impacting your ability to function at optimum levels. Feeling tired all the time likely means you’re struggling with sleep efficiency.

Sleep efficiency is the percentage of time spent in a deep sleep while you’re in bed. Normal sleep efficiency levels are 85% or higher. Less may signify a sleep disorder or medical condition.

Tiredness and Sleep Efficiency

People who aren’t hitting a high sleep efficiency mark are likely experiencing sleep deprivation, which can cause a host of mental and physical problems. For example, sleep is the period where your brain processes and catalogs the day’s events and turns them into memories. Not having this time can lead to short and long-term memory issues.

Sleep deprivation can also cause mood and behavioral changes, making a person feel moody, anxious, and even depressed. Being tired all the time also leads to brain fog, which can make it harder to perform daily duties at home and work. Brain fog contributes to poor concentration and focus, memory problems, and lack of mental clarity.

Physically, lack of sleep can weaken a person’s immune system and make them more susceptible to illness and disease. High blood pressure, weight gain, and increased risk of heart disease are all associated with chronic sleep deprivation. Plus, the confusion and bad balance caused by poor sleep put a person at a higher risk of accidentally injuring themselves or others.

Medical Conditions and Tiredness

Several medical conditions can also contribute to decreased sleep quality. For example, sleep apnea is a condition where a person involuntarily stops breathing during the night.

Sometimes people with sleep apnea are awoken by their own gasping, choking, or snoring, which can disrupt sleep cycles. Sleep apnea can cause a person to feel tired upon waking because their sleep was consistently interrupted — even if they don’t remember it.

Other medical conditions that can lead to sleep apnea include autoimmune diseases, such as lupus, arthritis, and Sjögren syndrome. Additionally, persistent fatigue can be caused by mental health conditions like depression, anxiety, and chronic stress.

Stress can have a direct effect on how tired you feel physically. When you anxiously ruminate or overwork your brain to the point of exhaustion, you burn through glucose — the brain’s fuel for working hard. This causes adenosine to rise, which blocks the release of the brain’s feel-good chemical, dopamine. Less dopamine leads to less motivation, which makes you less inclined to do anything mentally or physically, increasing overall fatigue.

Chronic Fatigue Syndrome

Another underlying condition that causes extreme tiredness is chronic fatigue syndrome (CFS). This causes exactly what it sounds like: chronic fatigue.

Chronic fatigue syndrome isn’t associated with any underlying disorders, though some specialists say it is induced by viral infections, stress, hormonal changes, or weakened immune systems. Women in their 40s and 50s tend to be the most commonly affected by this condition.

While everyone with CFS experiences different symptoms, it’s most commonly diagnosed when a person’s fatigue persists for at least six months and causes a significant reduction in their ability to perform everyday tasks.

Additionally, chronic fatigue can’t be cured by bed rest or significant periods of rest. CFS patients always wake up feeling tired, no matter how long they’ve slept. Chronic fatigue can manifest physically too, leading to muscle pain, joint pain, and swollen lymph nodes.

How to Stop Feeling Tired

If you’re feeling tired all the time, it might be time to change your sleeping, eating, and activity habits. Here’s how to stop feeling tired and improve your sleep quality to feel happier, healthier, and more well-rested.

Reduce Refined Foods and Increase Whole Foods

Most people understand that a balanced diet is important for maintaining physical health. But people don’t always associate unhealthy food with tiredness, even though it can be a major culprit of fatigue.

Reducing carbs like white breads, muffins, pastries, processed foods, and sweets can prevent bursts and dips in energy levels, especially when swapped for healthy foods like low-sugar fruits, vegetables, and lean protein.

Change When and How You Eat

If you skip breakfast, you could be setting yourself up for a day of sleepiness. While some people wait until lunch to eat due to fasting diets or busy schedules, studies have shown it may increase inflammation throughout the body

The quantity that you eat plays a role in how tired you feel too. Overeating or under-eating can both cause fatigue, so it’s important to practice portion control when it comes to meals. Getting enough whole grains, healthy fats, protein, and vegetables can boost energy levels after mealtimes, rather than draining them.

Stay Active and Lower Stress

As mentioned above, stress is a major contributor to tiredness. It can also rob you of quality sleep by keeping you up late into the night.

Getting regular exercise is one of the best ways to combat persistent stress. Instead of reaching for a cup of coffee, getting in a brisk 15-minute walk in the morning can boost circulation and increase cognitive sharpness, setting you up for an energized day.

While moving more may seem like the opposite of what you want to do when you’re tired, it works. “If you aren’t moving around, your body doesn’t need to use many resources to create energy, so energy production is low and you feel tired, fatigued, and unmotivated,” says doctor Roger Adams.

Once you start moving for at least 15 minutes, Adams says, your body will create enough energy to meet this demand. Another benefit of getting enough physical activity is that it can help you sleep better for longer.

Hydrate and Reduce Caffeine Intake

Many people turn to a cup of coffee for their morning energy boost, but this is a common cause of fatigue. There are several reasons why coffee causes low energy, especially when consumed regularly.

Mainly, coffee is a diuretic, meaning it causes a person to pass urine more often than normal. Diuretics can quickly lead to dehydration if a person isn’t drinking enough water. Dehydration increases heart rate and lowers blood pressure, both of which cause a person to feel more tired.

The negative effects of dehydration are why, even if you’re not a coffee drinker, getting enough water is essential to staying energized. One way to make sure you stay hydrated is to keep a glass of water or water bottle by your bedside or work table throughout the day. This way, getting enough water feels less like a chore and becomes a normal part of your everyday life.

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Get Your Energy Back

If you’re always feeling tired although you get enough sleep, it could be a sign that you’re suffering from a medical condition, so it’s important to talk to your doctor. But changing your daily habits can help you get back into dreamland faster. What you eat and how often you exercise are directly correlated with how tired you feel.

If you’re wondering how to stop feeling tired, you already have everything it takes to get back to feeling energized. Tiredness and sleep deprivation can have a major impact on your physical and mental health, so it’s important to take action and adopt healthy habits today.

Reading time: 4 min

Not getting enough sleep? You’re not alone. According to the CDC, more than one-third of adults don’t get the recommended seven hours of sleep they need to feel well-rested and energized the following day. When this occurs, we fall into what’s known as 6sleep debt.

Sleep debt, or sleep deprivation, occurs when you aren’t getting the sleep you need to feel awake, alert, and ready to go. And while one night of interrupted sleep may be a nuisance the following day, prolonged periods of sleep loss can lead to daytime sleepiness, emotional instability, weight gain, and several other health problems.

Why We Sleep

As human beings, our bodies require prolonged periods of rest not only to feel rejuvenated and refreshed but also to repair tissue, grow muscles, and synthesize hormones. We spend one-third of our lives asleep, and going without sleep can lead to psychosis or even death.

We can break down the stages of sleep into two primary categories: non-rapid eye movement and rapid eye movement (REM) sleep. Non-REM slow-wave deep sleep is characterized by slow brain waves and the release of growth hormones as our brain and many physiological systems enter a state of repair. REM sleep is similar to how our mind operates during the day, with one caveat — the brain is active and working, but our muscles are in a state of paralysis.

Beyond these realities, scientists don’t fully understand why we sleep. Some propose that sleep restores the brain’s energy while others hypothesize that sleep plays a major role in the connectivity and plasticity of the brain. The latter theory explains why individuals who are sleep-deprived suffer from memory loss and the inability to pay attention.

Regardless of the underlying reasons behind our need for sleep, we ultimately know that sleep is an extremely important aspect of our well-being. Without it, we suffer.

What Is Sleep Debt?

Sleep debt is the act of not getting enough sleep. You can often gauge whether or not you’re receiving enough sleep by monitoring how you feel the following day. If you’re tired, drowsy, and inattentive, chances are you’re suffering from short-term sleep debt. And if symptoms such as blood pressure changes, weight gain, or other serious health problems take shape over time, you may be suffering from the cumulative effects of chronic sleep debt.

The Symptoms of Sleep Debt

The primary short-term symptom of sleep debt is excessive daytime sleepiness. Other symptoms may include the following:

Irritability
Depressed mood
Forgetfulness
Clumsiness
Lack of motivation
Increased appetite
Carbohydrate cravings
Reduced sex drive
Inability to concentrate
Fatigue

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The Effects of Sleep Debt

Sleep loss in any form can come with serious side effects that will impact both your short-term and long-term health. Here’s a look at some of these effects.

Weight Gain

The hormones leptin and ghrelin control feelings of hunger and fullness. When you suffer from lack of sleep, leptin will decrease and lead to the constant feeling of hunger alongside a general slowdown of your metabolism, which may cause weight gain over time. Ghrelin will increase with lack of sleep increasing hunger levels.  Also, keep in mind that getting plenty of sleep can burn calories.

Blood Pressure & Heart Disease

During normal sleep, your blood pressure will naturally decrease. If you’re suffering from a sleep deficit, your blood pressure will stay higher for a longer period of time, just as it does during the day. Over time, this may lead to an increased risk of heart disease, thus illustrating the need for a normal sleep schedule.

Type 2 Diabetes

Diabetes is a disease that causes sugar to build up in your blood, which will damage your blood vessels over time. According to the National Sleep Foundation, when your sleep patterns are negatively impacted, less insulin is released into the bloodstream after you eat.

Meanwhile, your body may release other stress hormones to help you stay awake. These stress hormones impact the ability of insulin to do its job effectively. As a result, glucose will remain in your bloodstream and increase your risk of type 2 diabetes.

Sleep Debt Treatments

Treating sleep debt in any form is only required if you physically can’t go to sleep or suffer from a sleep disorder, such as sleep apnea. Oftentimes you can improve sleep debt by simply increasing the amount of time you’re asleep or by altering your sleep habits to further encourage healthy amounts of sleep.

If you physically can’t go to sleep or you suffer from a sleep disorder, two primary avenues exist that can treat your sleep deprivation: cognitive treatments and medications.

Cognitive Treatment

Cognitive treatments that seek to repay your sleep debt are available in abundance. For instance, relaxation and meditation techniques utilize guided breathing and mindfulness approaches that encourage your body and mind to fall asleep naturally.

Other cognitive treatments include controlling pre-bedtime activities and optimizing your sleep environment to increase your sleep duration. This may include limiting social media usage before bed and removing other distractions like bright lights or screens.

Medications

If the cognitive or non-medical intervention proves to be ineffective, sleep medicines are available that can help induce sleep. Some of these medications are available over-the-counter while others require a prescription.

Some individuals may form a dependence on sleeping medications, meaning they can’t go to sleep without taking medication. For this reason, it’s important to speak with your healthcare provider and review all your options before determining if sleep medication is right for you.

Habits for Healthy Sleep

Getting a good night’s sleep is dependent upon your sleeping habits and nightly routines. Also known as sleep hygiene, healthy sleep habits will leave you feeling rested and refreshed each morning.

Some good sleep habits include:

Going to bed when you feel tired
Not eating 2-3 hours before bed
Engaging in regular, daily exercise
Keeping the bedroom quiet and cool
Turning off electronic devices
Using an alarm clock to regulate when you wake up

Paying off sleep debt

If you fail to get your recommended amount of sleep, you’ll begin accumulating a sleep debt. For instance, if you need eight hours of sleep but only get five, you’ll have a sleep debt of three hours. If this pattern continues throughout the week, your sleep debt will climb, and the effects of sleep deprivation will quickly take hold.

The only way to pay off your sleep debt is to start getting the sleep you need, along with some extra time each night, or with naps, until the debt is fully ”paid off”. Once you’ve paid off the sleep debt, you can resume your normal sleeping schedule. 

Even if paying off your sleep debt seems impossible, remember that it can be done with conscious effort. While repaying tens or even hundreds of hours of sleep debt may seem out of reach, it can be accomplished by reflecting on your current sleep habits and making adjustments whenever necessary.

Consider using a sleep tracker to fully understand your sleeping habits. Once you’ve finally woken up feeling refreshed and recovered, you’ll have paid off your sleep debt in full.

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What is it?

Oxygen saturation refers to the percentage of hemoglobin that is bound to oxygen when in the artery. Hemoglobin is the protein in red blood cells that binds oxygen, carbon dioxide, and carbon monoxide. Since arterial blood is on the way to the capillaries from the left ventricle of the heart, a high amount of oxygen is expected on hemoglobin, typically greater than 95% saturation.

This oxygen is what is required for metabolic processes, namely ATP production, which provides the energy necessary for vital function. Reduction in oxygen carrying capacity often results in altered or diminished cellular and bodily functions, which can lead to acute or chronic disorders.

How it’s measured

Oxygen saturation is measured non-invasively by photoplethysmography (PPG). PPG utilizes red and infrared light exposure through the skin, which absorbs much of the light. Each form of hemoglobin (unbound or bound to oxygen, carbon dioxide, carbon monoxide) absorbs wavelengths of light differently.

Oxygenated hemoglobin absorbs more infrared light, whereas deoxygenated hemoglobin absorbs more red light. By understanding the light absorption curves of each kind of hemoglobin at red and IR wavelengths, the amount of oxygen-carrying hemoglobin relative to total hemoglobin can be determined and expressed as a percentage.

Correlation with health conditions

Because normal function depends on aerobic processes, impairment of oxygen delivery can lead to worsening symptoms, diminished function, and decreased ability to recover.

Many clinical settings use oxygen saturation to monitor the severity and progression of illnesses. SpO2 is a predictor of all-cause mortality and mortality caused by pulmonary diseases.

What is a “normal” range?

Oxygen saturation greater than 95% is considered normal. Values between 90-95% represent a slightly blunted capacity to carry oxygen and may or may not indicate a significant deviation from normal. However, oxygen saturation below 90% (hypoxemia) is considered low and usually suggests an abnormality in oxygen handling.

95% = Normal
90-95% = Low
<90% = Hypoxemia

For individuals with chronic lung conditions or breathing problems, these “normal” ranges typically do not apply. In these cases, individuals should consult with their healthcare professional for information on acceptable oxygen levels.

Interpreting trends

Deep sleep is a complex biometric that is difficult to quantify. EEG devices provide a strong understanding of sleep stages and progressions but are less realistic for an individual on a regular basis. However, using accelerometers and PPG wearables, light and deep sleep can be approximated on a nightly basis and easily tracked over time.

As with total sleep duration, tracking deep sleep can provide insight into its contribution to changes in health-related outcomes. As a more challenging variable to quantify, monitoring deep sleep over time can also provide insight into lifestyle changes and how they affect deep sleep. For example, tracking how a medication affects deep sleep may provide insight into its efficacy or side effects.

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Biostrap

In a 2018 study, the standard deviation of absolute error in SpO2 values from clinical reference devices was 1.41. Researchers concluded that this preliminary data suggests that this device may be suitable for prospective clinical trials such as evaluating the utility of wearable physiological monitoring in digitally-enabled preventative service models for respiratory disorders.

In another 2018 study published in Circulation investigating the utility of the Biostrap device as a screening tool for Obstructive Sleep Apnea, researchers concluded that the correlation between the Biostrap and clinical reference PSG support further evaluation of wrist-worn health wearables for OSA screening in high risk CVD patients.

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What is it?

Respiratory rate is the rate at which a complete breathing cycle occurs. While voluntary control can take over this, respiratory rate is an autonomic process controlled by the autonomic nervous system. This happens due to many inputs, including the brain’s respiratory center, which collects physiological sensory information throughout the body.

These sensory inputs into the respiratory center of the brain include blood CO2, O2, and pH levels, lung stretch receptors, joint and muscle proprioceptors, other peripheral receptors, and additional information from higher brain centers that process emotion, speech, motor pathways, voluntary control, and more

How is it measured?

Respiratory rate can be measured through photoplethysmography (PPG) by measuring the baseline shifts that occur with breathing. The baselines move up and down in an oscillatory pattern corresponding to the breath cycle.

Correlations with health conditions

Respiratory rate is subject to change and may be an important vital sign to monitor. The two primary drivers of these changes are lung complications and sympathetic stress response.

Alterations to lung function, such as acute respiratory illnesses (pneumonia, upper respiratory tract infection, etc.), acute bronchoconstriction (such as asthma), and chronic illnesses (COPD, emphysema, pulmonary fibrosis, etc.) all can cause impaired gas exchange at the levels of the lung.

This impaired gas exchange leads to acidosis (increased acidity in the blood) and hypercapnia (a condition of abnormally elevated carbon dioxide levels in the blood), which increase the respiratory rate through the respiratory control center. Through different mechanisms, sympathetic stress leads to increased respiratory rate, typically viewed as an anticipatory response to stress.

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Normal or Acceptable Range

Breathing rate is individual-specific but can range from 12 to 20 breaths per minute (bpm). Within a particular individual, the breathing rate can stay relatively constant across days at basal levels (coefficient of variation ~ 5%). However, certain factors such as respiratory illness, high levels of fatigue, infection, and more can cause the respiratory rate to change significantly.

Interpreting Trends

This combination of low variability but high responsiveness allows the respiratory rate to be a good indicator of acute problems. For example, the respiratory rate appears to be highly predictive of respiratory infection and responds before a typical diagnosis, which makes for an excellent biomarker for predicting the risk of respiratory infection.

In general, besides acute illnesses, the respiratory rate should remain relatively stable or trend downward with increased cardiorespiratory function.

References

  1. Schaefer KE. Respiratory Pattern and Respiratory Response to CO2. Journal of Applied Physiology. 1958;13(1):1–14. doi:10.1152/jappl.1958.13.1.1
  2. Javaheri S, Kazemi H. Metabolic alkalosis and hypoventilation in humans. The American Review of Respiratory Disease. 1987;136(4):1011–1016. doi:10.1164/ajrccm/136.4.1011
  3. Brinkman JE, Toro F, Sharma S. Physiology, Respiratory Drive. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021. http://www.ncbi.nlm.nih.gov/books/NBK482414/
  4. Schelegle ES, Green JF. An overview of the anatomy and physiology of slowly adapting pulmonary stretch receptors. Respiration Physiology. 2001;125(1):17–31. doi:10.1016/S0034-5687(00)00202-4
  5. Bishop B, Bachofen H. COMPARATIVE INFLUENCE OF PROPRIOCEPTORS AND CHEMORECEPTORS IN THE CONTROL OF RESPIRATORY MUSCLES. :10.
  6. Guz A. Brain, breathing and breathlessness. Respiration Physiology. 1997;109(3):197–204. doi:10.1016/S0034-5687(97)00050-9
  7. Miller DJ, Capodilupo JV, Lastella M, Sargent C, Roach GD, Lee VH, Capodilupo ER. Analyzing changes in respiratory rate to predict the risk of COVID-19 infection. PLOS ONE. 2020;15(12):e0243693. doi:10.1371/journal.pone.0243693
  8. Sun G, Okada M, Nakamura R, Matsuo T, Kirimoto T, Hakozaki Y, Matsui T. Twenty‐four‐hour continuous and remote monitoring of respiratory rate using a medical radar system for the early detection of pneumonia in symptomatic elderly bedridden hospitalized patients. Clinical Case Reports. 2018;7(1):83–86. doi:10.1002/ccr3.1922
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What is it?

Heart rate is defined as the number of contractions of the heart, expressed in beats per minute (bpm). The heart rate is a function of local electrical signals in the cardiac cells, neural inputs, and hormonal influence.

Heart rate changes in response to stressors in order to increase circulation of blood, often by increasing cardiac output. This increase in cardiac output helps meet the demands of physiological responses to stress.

Therefore, heart rate can be a valuable metric in understanding the cumulative stress (e.g. emotional and physical stress) that is placed on the body.

How it’s measured

Heart rate can be measured through palpation, electrocardiography (ECG), and photoplethysmography (PPG). Biostrap measures heart rate using PPG, which captures pulse waves of blood flow using red and infrared light. By using the count of pulse waves per unit of time, heart rate in bpm can be obtained.

Heart rate can be measured during activity (active heart rate). However, resting heart rate (RHR) is most often used to clinically assess cardiovascular health, since extra stress on the cardiovascular system is absent. RHR can be subject to acute stress, including observation bias. Therefore, passive collection of RHR through wearables, particularly during sleep, allows for minimizing error that may artificially raise RHR.

Correlation with health conditions

Chronically increased resting heart rate has been correlated with many diseases and their outcomes, particularly hypertension, obesity, cardiovascular diseases, cancer, and metabolic disorders, among others. In many cases, the increased heart rate is not itself a contributor to the disease progression, but rather a signal that there are down-stream effects of the underlying disease.

Acutely increased resting heart rate may be an indication of altered blood flow, reduced plasma volume, psychological stress, activity, infection, and thermal stress. Monitoring heart rate trends can alert when heart rate has changed acutely, but may not be indicative of the cause of the increase. In times where no change in RHR is expected such as during sleep, follow-up evaluation may be warranted.

What is a “normal” range?

<60 bpm = Bradycardia
60-100 bpm = “Normal”
>100 = Tachycardia

A “normal” RHR is considered to be 60-100 beats per minute. Factors that may influence resting heart rate values include:

  • Fitness level
  • Room temperature
  • Body position
  • Emotional stress
  • Body size and/or composition
  • Use of medications

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Interpreting trends

Resting heart rate, measured over time, provides insights into cardiovascular changes in response to lifestyle or disease progression. Since RHR responds relatively quickly to lifestyle changes, tracking resting heart rate over time is recommended in order to monitor positive and negative health adaptations.

Although RHR alone is not enough to diagnose any particular disease, the American Heart Association recommends lowering resting heart rate as much as possible. Exercise training, dietary changes, meditation, and reducing stress are examples of ways to reduce RHR. The decrease in heart rate reflects increased cardiovascular efficiency and decreased systemic stress.

Increases in RHR over time could be an indication of negative cardiovascular changes, and may warrant follow-up testing or lifestyle intervention.

Biostrap

In a clinical study, the Biostrap PPG-based resting heart rate measurement matched within 1 +/- BPM to the reference research grade ECG.

In a small real-world cohort of elderly people, the standalone Fibricheck AF algorithm can accurately detect AF using Wavelet wristband-derived PPG data. Results are comparable to the Alivecor Kardia one-lead ECG device, with an acceptable unclassifiable/bad quality rate. This opens the door for long-term AF screening and monitoring.

References

  1. Lakatta EG, Vinogradova TM, Maltsev VA. The Missing Link in the Mystery of Normal Automaticity of Cardiac Pacemaker Cells. Annals of the New York Academy of Sciences. 2008;1123(1):41–57. doi:https://doi.org/10.1196/annals.1420.006
  2. Brack KE, Coote JH, Ng GA. Interaction between direct sympathetic and vagus nerve stimulation on heart rate in the isolated rabbit heart. Experimental Physiology. 2004;89(1):128–139. doi:https://doi.org/10.1113/expphysiol.2003.002654
  3. Furnival CM, Linden RJ, Snow HM. The inotropic and chronotropic effects of catecholamines on the dog heart. The Journal of Physiology. 1971;214(1):15–28.
  4. Sneddon G, Mourik R van, Law P, Dur O, Lowe D, Carlin C. P177 Cardiorespiratory physiology remotely monitored via wearable wristband photoplethysmography: feasibility and initial benchmarking. Thorax. 2018;73(Suppl 4):A197–A197. doi:10.1136/thorax-2018-212555.334
  5. Lequeux B, Uzan C, Rehman MB. Does resting heart rate measured by the physician reflect the patient’s true resting heart rate? White-coat heart rate. Indian Heart Journal. 2018;70(1):93–98. doi:10.1016/j.ihj.2017.07.015
  6. Paul Laura, Hastie Claire E., Li Weiling S., Harrow Craig, Muir Scott, Connell John M.C., Dominiczak Anna F., McInnes Gordon T., Padmanabhan Sandosh. Resting Heart Rate Pattern During Follow-Up and Mortality in Hypertensive Patients. Hypertension. 2010;55(2):567–574. doi:10.1161/HYPERTENSIONAHA.109.144808
  7. Aune D, Sen A, ó’Hartaigh B, Janszky I, Romundstad PR, Tonstad S, Vatten LJ. Resting heart rate and the risk of cardiovascular disease, total cancer, and all-cause mortality – A systematic review and dose-response meta-analysis of prospective studies. Nutrition, metabolism, and cardiovascular diseases: NMCD. 2017;27(6):504–517. doi:10.1016/j.numecd.2017.04.004
  8. Lee DH, Park S, Lim SM, Lee MK, Giovannucci EL, Kim JH, Kim SI, Jeon JY. Resting heart rate as a prognostic factor for mortality in patients with breast cancer. Breast Cancer Research and Treatment. 2016;159(2):375–384. doi:10.1007/s10549-016-3938-1
  9. Hillis GS, Woodward M, Rodgers A, Chow CK, Li Q, Zoungas S, Patel A, Webster R, Batty GD, Ninomiya T, et al. Resting heart rate and the risk of death and cardiovascular complications in patients with type 2 diabetes mellitus. Diabetologia. 2012;55(5):1283–1290. doi:10.1007/s00125-012-2471-y
  10. Jiang X, Liu X, Wu S, Zhang GQ, Peng M, Wu Y, Zheng X, Ruan C, Zhang W. Metabolic syndrome is associated with and predicted by resting heart rate: a cross-sectional and longitudinal study. Heart. 2015;101(1):44–49. doi:10.1136/heartjnl-2014-305685
  11. Lee B-A, Oh D-J. The effects of long-term aerobic exercise on cardiac structure, stroke volume of the left ventricle, and cardiac output. Journal of Exercise Rehabilitation. 2016;12(1):37–41. doi:10.12965/jer.150261
  12. Target Heart Rates Chart. www.heart.org. [accessed 2021 Apr 15]. https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
  13. Reimers AK, Knapp G, Reimers C-D. Effects of Exercise on the Resting Heart Rate: A Systematic Review and Meta-Analysis of Interventional Studies. Journal of Clinical Medicine. 2018;7(12). doi:10.3390/jcm7120503
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What is it?

Heart rate variability (HRV) is a measure of differences in the time intervals between heart beats. Heart rate by itself is the expression of how many contractions of the heart there are in a given unit of time; however, the rate itself is not constant. There is normal fluctuation of time between heartbeats, in a manner that speeds up and slows down heart rate. Therefore, HRV is a quantifiable measure that assesses these differences.

This variation in the time between heartbeats is thought to be a composite measure of parasympathetic and sympathetic neural inputs and hormonal inputs as regulated by the autonomic nervous system. Much is still unknown about the mechanism of action causing variability changes. However, many studies have shown correlations between HRV and diseased states, such as heart disease, Parkinson disease, and cardiovascular disease; emotional stress, such as depression; physical/mechanical stress, such as high-intensity or resistance training; sleep in the context of both acute stress and chronic stress; and meditation whether it’s “inward- attention” or Vipassana meditation. Therefore, HRV is becoming a more common non-invasive measure to examine the physiological state and responses.

How it’s measured

HRV can be measured by use of an electrocardiogram (ECG) or photoplethysmography (PPG). By referencing a common point in the ECG or PPG waveform, the time between each heart beat can be recorded in milliseconds (ms). Collecting each beat-to-beat interval in ms allows us to compute HRV, most commonly reported as rMSSD (root mean square of successive differences)

The rMSSD method of calculation takes each interval, squares the interval, takes the overall mean, and then the square root of that mean is taken. Biostrap computes the rMSSD using this method and remains the standard computational method for HRV. 

More complex measures of HRV, including frequency domain analysis can be performed to get further information out of heart rate patterns, which will be covered in another review. 

Correlation with health conditions

HRV is most notably correlated with stress conditions, such as anxiety disorders, depression, PTSD, and other psychological states, with lower HRV indicating higher-stressed states. The suggested mechanism is an increased sympathetic arousal, which affects HRV; HRV alone does not cause these states, but reflects and provides insight into the heightened stress on the physiological systems, which in turn have effects on other bodily systems, particularly the cardiovascular and endocrine systems. 

Because of the chronic effects of stress, as previously mentioned, HRV has been noted to be a predictor of all-cause mortality and correlated with obesity, cardiovascular disease, cancer, and neurodegenerative diseases, among other health conditions.

What is a “normal” range?

Heart rate variability has a large individual component and is often used to assess changes in health over time (see “Interpreting Trends” below).

Heart rate variability can fluctuate day-to-day based on exposure to stress, sleep quality, diet, and exercise. This leads to low repeatability, and therefore makes normative data difficult to collect.

In general, younger individuals, males, and more active individuals tend to have higher heart rate variability. However, the inter-subject variability tends to be too high to suggest proper normative ranges. This demonstrates a need to track HRV over time to understand the ‘profile’ of an individual.

When considering a normal range, there is not a normal scale of 0-100. HRV scale is 0-255. Many factors influence where your HRV sits on this scale, including; genetics, lifestyle, and age. Once you track HRV over a period of time you will have a baseline HRV. Once a baseline is established you will be able to see how day-to-day internal and external stressors influence your HRV, upward or downward.

Watching your HRV deviate positively or negatively from your baseline is the most important factor to observe. The actual HRV number matters less than how much it has varied from your “normal” baseline.

Interpreting trends

As previously mentioned, HRV is difficult to interpret and generally a nonspecific data point from a single spot check. However, since it is a dynamic measure that responds to various lifestyle factors, tracking HRV over time allows for non-invasive insight into changes in health status or efficacy of certain interventions.

In general, since higher HRV is preferable, a greater ability to manage stress results in an increased HRV. The results of the studies demonstrating the relationship between stress and HRV suggest that interventions aimed at reducing mental and physical stress could increase HRV and minimize day-to-day fluctuations. The increase in HRV itself will not reduce risk and improve health over the long term, but rather, it reflects positive changes in an individual’s physiology.

Biostrap

In a 2018 study, the Biostrap sensor as a wrist-worn device was shown to produce high-quality signals which are useful for the estimation of heart rate variability. 

References

  1. Mccraty R, Shaffer F. Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health Risk. Global Advances in Health and Medicine. 2015;4(1):46–61. doi:10.7453/gahmj.2014.073
  2. Silva LEV, Silva CAA, Salgado HC, Fazan R. The role of sympathetic and vagal cardiac control on complexity of heart rate dynamics. American Journal of Physiology-Heart and Circulatory Physiology. 2016;312(3):H469–H477. doi:10.1152/ajpheart.00507.2016
  3. Dobrek Ł, Skowron B, Baranowska A, Malska-Woźniak A, Ciesielczyk K, Thor PJ. Spectral heart rate variability and selected biochemical markers for autonomic activity in rats under pentobarbital anesthesia. Polish Annals of Medicine. 2017;24(2):180–187. doi:10.1016/j.poamed.2017.01.001
  4. Huikuri HV, Mäkikallio TH. Heart rate variability in ischemic heart disease. Autonomic Neuroscience. 2001;90(1):95–101. (Neural Regulation of Cardiovascular Function Explored in the Frequency Domain). doi:10.1016/S1566-0702(01)00273-9
  5. Alonso A, Huang X, Mosley TH, Heiss G, Chen H. Heart rate variability and the risk of Parkinson disease: The Atherosclerosis Risk in Communities study. Annals of Neurology. 2015;77(5):877–883. doi:https://doi.org/10.1002/ana.24393
  6. Thayer JF, Yamamoto SS, Brosschot JF. The relationship of autonomic imbalance, heart rate variability and cardiovascular disease risk factors. International Journal of Cardiology. 2010;141(2):122–131. doi:10.1016/j.ijcard.2009.09.543
  7. McCraty R, Atkinson M, Tiller WA, Rein G, Watkins AD. The effects of emotions on short-term power spectrum analysis of heart rate variability. The American Journal of Cardiology. 1995;76(14):1089–1093. doi:10.1016/S0002-9149(99)80309-9
  8. CARNEY RM, FREEDLAND KE. Depression and heart rate variability in patients with coronary heart disease. Cleveland Clinic journal of medicine. 2009;76(Suppl 2):S13–S17. doi:10.3949/ccjm.76.s2.03
  9. Sarmiento S, García-Manso JM, Martín-González JM, Vaamonde D, Calderón J, Da Silva-Grigoletto ME. Heart rate variability during high-intensity exercise. Journal of Systems Science and Complexity. 2013;26(1):104–116. doi:10.1007/s11424-013-2287-y
  10. Kingsley JD, Figueroa A. Acute and training effects of resistance exercise on heart rate variability. Clinical Physiology and Functional Imaging. 2016;36(3):179–187. doi:https://doi.org/10.1111/cpf.12223
  11. Hall M, Vasko R, Buysse D, Ombao H, Chen Q, Cashmere JD, Kupfer D, Thayer JF. Acute Stress Affects Heart Rate Variability During Sleep. Psychosomatic Medicine. 2004;66(1):56–62. doi:10.1097/01.PSY.0000106884.58744.09
  12. da Estrela C, McGrath J, Booij L, Gouin J-P. Heart Rate Variability, Sleep Quality, and Depression in the Context of Chronic Stress. Annals of Behavioral Medicine. 2021;55(2):155–164. doi:10.1093/abm/kaaa039
  13. Busek P, Vanková J, Opavsky J, Salinger J, Nevsimalova S. Spectral analysis of heart rate variability in sleep. Physiological research / Academia Scientiarum Bohemoslovaca. 2005;54:369–76.
  14. Krygier JR, Heathers JAJ, Shahrestani S, Abbott M, Gross JJ, Kemp AH. Mindfulness meditation, well-being, and heart rate variability: A preliminary investigation into the impact of intensive Vipassana meditation. International Journal of Psychophysiology. 2013;89(3):305–313. (Psychophysiology in Australasia – ASP conference – November 28-30 2012). doi:10.1016/j.ijpsycho.2013.06.017
  15. Wu S-D, Lo P-C. Inward-attention meditation increases parasympathetic activity: a study based on heart rate variability. Biomedical Research. 2008;29(5):245–250. doi:10.2220/biomedres.29.245
  16. Jarchi D, Salvi D, Velardo C, Mahdi A, Tarassenko L, Clifton DA. Estimation of HRV and SpO2 from wrist-worn commercial sensors for clinical settings. In: 2018 IEEE 15th International Conference on Wearable and Implantable Body Sensor Networks (BSN). 2018. p. 144–147. doi:10.1109/BSN.2018.8329679
  17. Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Frontiers in Public Health. 2017 [accessed 2021 Apr 14];5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5624990/. doi:10.3389/fpubh.2017.00258
  18. Chalmers JA, Quintana DS, Abbott MJ-A, Kemp AH. Anxiety Disorders are Associated with Reduced Heart Rate Variability: A Meta-Analysis. Frontiers in Psychiatry. 2014 [accessed 2021 Apr 21];5. https://www.frontiersin.org/articles/10.3389/fpsyt.2014.00080/full. doi:10.3389/fpsyt.2014.00080
  19. Hauschildt M, Peters MJV, Moritz S, Jelinek L. Heart rate variability in response to affective scenes in posttraumatic stress disorder. Biological Psychology. 2011;88(2):215–222. doi:10.1016/j.biopsycho.2011.08.004
  20. Cohen H, Kotler M, Matar MA, Kaplan Z, Miodownik H, Cassuto Y. Power spectral analysis of heart rate variability in posttraumatic stress disorder patients. Biological Psychiatry. 1997;41(5):627–629. doi:10.1016/S0006-3223(96)00525-2
  21. Tsuji H, Venditti F J, Manders E S, Evans J C, Larson M G, Feldman C L, Levy D. Reduced heart rate variability and mortality risk in an elderly cohort. The Framingham Heart Study. Circulation. 1994;90(2):878–883. doi:10.1161/01.CIR.90.2.878
  22. Karason K, Mølgaard H, Wikstrand J, Sjöström L. Heart rate variability in obesity and the effect of weight loss. The American Journal of Cardiology. 1999;83(8):1242–1247. doi:10.1016/S0002-9149(99)00066-1
  23. Stein PK, Reddy A. Non-Linear Heart Rate Variability and Risk Stratification in Cardiovascular Disease. Indian Pacing and Electrophysiology Journal. 2005;5(3):210–220.
  24. Sandercock G. Normative values, reliability and sample size estimates in heart rate variability. Clinical Science. 2007;113(3):129–130. doi:10.1042/CS20070137

 

Reading time: 5 min

Melatonin supplements have been used for decades to promote sound, natural sleep. This natural hormone that’s also produced by our brain’s pineal gland. More on this in just a moment.

While melatonin may help combat sleep problems or even sleep disorders, recent clinical trials suggest this natural hormone can improve anxiety disorders too. Some believe this is because melatonin improves sleep, which reduces anxiety, while others suspect melatonin may directly impact anxiety symptoms to counteract this mental health disorder.

So, what’s really happening beneath the surface? Read on to learn how melatonin may help your anxiety, how you can use it, what potential side effects it may have, and more.

What Is Melatonin?

Melatonin is a hormone produced primarily at night by the pineal gland that regulates your circadian rhythm — the 24-hour sleep-wake cycle that tells us to sleep when it’s dark and stay awake during the day. Circadian rhythms are often controlled internally, but external factors, like sunlight, temperature, exercise, and more, can influence these rhythms as well.

In a perfect scenario, the pineal gland will secrete higher levels of melatonin at night to help you fall asleep and stay asleep. When morning comes, melatonin levels will fall and cortisol begins to rise to signal to your body that it’s time to slowly start waking up.

Unfortunately, this doesn’t always happen so effortlessly.

Factors such as noise, light, stress, working hours, jet lag, lack of exercise, poor diet, and many other factors can cause your body to produce low levels of melatonin. If your levels of melatonin are hindered, you may experience sleep deprivation, fatigue, or mood disorders among countless other troubles.

Fortunately for us, if we’re tossing and turning at night due to loud noises, bright lights, or a lack of melatonin production, we can take melatonin supplements to help us fall asleep.

Sleep and Mental Health

You may now be wondering how melatonin production relates to mental health. What does a hormone that aids in sleep regulation have to do with anxiety anyway? To answer this question, let’s take a step back to focus not on melatonin, but on sleep.

Sleep and mental health are very closely connected. Every 90 minutes or so, a healthy individual will cycle between four phases of sleep. Body temperature drops and heart rate slows during the first sleep phase. By the fourth phase, your body is working much harder than you’d think, performing physiological changes that boost your immune system and prepare your nervous system for another day.

Sleep disturbances that disrupt this transition between stages of sleep can wreak havoc on your brain. Your cognitive function may become impaired, stress hormones may be released, and above all else, your emotional regulation may not function as it should.

If this happens once, you can go to bed early the next night and make up for lost sleep without worry. Consider tracking your sleep with Biostrap’s Recover Set to gain valuable insights into the quality of your sleep, including sleep stages, movement, and awakenings, and how your nervous system recovers and adapts to stressors on any given night.

If your sleep efficiency is repeatedly impacted, your mental health may suffer in return. 

This is where melatonin may come to the rescue. By taking melatonin, you can help your body get the sleep it needs to recover well both physically and mentally. Melatonin treatment can be an efficient sleep aid that promotes healthier, consistent sleep. These positive effects of melatonin can thereby ensure your mind and body are healthy and ready to go, each and every morning.

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Melatonin for Anxiety: What the Research Says

Now that we’ve drawn a connection between melatonin and mental health, let’s take a closer look at the evidence and systematic reviews that support these claims.

Much of the human research on melatonin has been conducted on patients undergoing a surgical procedure. Surgery is often a stressful and anxiety-inducing process, and medications are often used to curb such anxiety. But recent research suggests melatonin may be equally as effective as prescription medication.

A 2015 meta-analysis that looked at studies comparing the use of melatonin to anti-anxiety medication and a placebo sugar pill found that taking melatonin before surgery was more effective at reducing anxiety than the sugar pill. Most studies also suggested melatonin was equally as effective as the heavier medication.

Some studies found that melatonin also helped reduce anxiety after the procedure, but other studies found no benefit.

A 2018 study found that melatonin helped reduce anxiety as well as an oral Alprazolam, a sedative drug used to promote sleep before surgery. A separate 2018 study that evaluated people who’d undergone heart surgery found that melatonin worked better than Oxazepam when it came to improving sleep and reducing the symptoms of anxiety after surgery.

From these studies, we can conclude that melatonin may effectively reduce anxiety before and after surgery, though we don’t yet know if it’s equally effective with other forms of anxiety such as panic attacks. More clinical studies are needed.

Different Forms of Anxiety

It’s important to keep in mind that anxiety is an umbrella term used to describe conditions that are characterized by feelings of worry, anxiousness, or fear that impact your daily life and performance. While some evidence suggests melatonin administration may help with anxiety, it’s not yet clear what forms of anxiety can be treated.

For this reason, it’s important to speak with your doctor before taking melatonin for anxiety. A healthcare professional is better equipped to understand the causes of your anxiety and work through them with you. 

Using Melatonin for Anxiety

Using melatonin for anxiety is as simple as taking a melatonin supplement before bed. These supplements come in tablet form and can be taken by mouth or dissolved under the tongue. Clinical studies suggest taking 3-10 milligrams before bed for optimal results. Higher doses of melatonin do not necessarily work better. However, age, body weight, and sensitivity to melatonin may affect the recommended dosage.

As you begin looking for melatonin supplements, look for reputable, high-quality options. Supplements like melatonin aren’t regulated by the Food and Drug Administration (FDA), so it pays to do your research and find reliable and trusted sources. For example, some supplements are verified by the United States Pharmacopeia, which means they’ll be free of contaminants and safe to consume.

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Side Effects and Risks

Supplementing with melatonin is a simple and low-risk option. While its short-term use has been found safe, more studies are needed to evaluate any long-term use effects. Unwanted side effects or adverse events rarely occur, and they’re often mild if they do. 

According to the Mayo Clinic, side effects may include headaches, dizziness, nausea, or upset stomach. Additionally, melatonin may interact with blood thinners, blood pressure medication, and other medications that cause sleepiness.

If you’re an older adult or you happen to suffer from a medical condition that requires medications such as these, speak with your doctor to determine if melatonin is right for you. They may be able to offer an alternative medication to help you find short-term or long-term relief from anxiety.

Should You Take Melatonin for Anxiety?

Melatonin has been studied as an alternative and natural sleep aid for decades, but research hasn’t yet determined if it works for all forms of anxiety. Consider talking with your doctor to determine if using melatonin for anxiety is the right choice for you. If the root cause of your anxiety is due to poor sleep quality, melatonin could be the key to falling asleep with ease and waking up feeling well-rested and ready to conquer the day.

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When it comes to getting enough sleep, we have a habit of trying to cut corners. Seven or eight hours of sleep may sound ideal, but rarely do we seem to have the time.

According to the National Sleep Foundation, older adults should sleep between 7-9 hours each night. This recommendation only increases amongst teenagers, preschoolers, and toddlers. Yet despite this advice, 45% of Americans say that poor or insufficient sleep has affected their daily lives at least once in the past week.

Getting a good night’s sleep isn’t easy, but it’s essential. Let’s pull down the sheets to learn more about sleep, why 6 hours of sleep simply isn’t enough for most people, and what we can do to ensure we’re getting the hours of shuteye we need.

The Basics of Sleep

There are four primary stages of sleep to be aware of, and we collectively refer to these stages as the sleep cycle.

The first stage is the lightest stage of sleep when you’re just dozing off. During this stage of drowsy sleep is when you may experience slight twitching such as Hypnic jerks, and you can also easily be woken. Your muscles will relax and your brain will begin to slow down as your body prepares for a more restful, deep sleep.

The second stage of sleep is when body temperature will begin to drop and heart rate and breathing rate both slightly decrease. You can’t be woken as easily during this stage of sleep, and your brain will continue to slow down as bursts of brain activity called sleep spindles occur. Research suggests sleep spindles protect the brain from awakening during sleep.

The third stage of sleep is known as slow-wave sleep. This is the most restorative stage of sleep and is marked by delta brain waves. Some of the most essential bodily processes occur during this stage including hormonal balancing, human growth hormone release, brain detoxification and memory consolidation.

The fourth and final stage of sleep is known as rapid eye movement, or REM, sleep, and this is where dreaming takes place. While your muscles will be “paralyzed”, brain waves will become more active, behaving nearly as if you were awake. Getting an adequate amount of REM sleep is very important for cognitive functions as well as memory. 

Generally speaking, your body will spend more time in deep sleep during the first half of the night and more in REM during the second half.

Ensuring you reach each of these four stages of the sleep cycle is extremely important. One sleep cycle, which will include all four stages of sleep, will often last approximately 100-120 minutes, and you’ll transition through four or five full cycles per night.

For Most Of Us, 6 Hours of Sleep Isn’t Enough

We hate to burst your bubble, but six hours of sleep just isn’t enough for the average individual. While some people do well on only six hours of sleep, most of us would benefit from an extra hour or two of additional rest. Below we’ve included the nine primary sleep groups identified by the Centers for Disease Control and Prevention, along with their corresponding sleep recommendations.

Newborns
​Newborns should receive between 14 and 17 hours of sleep, though 11 to 13 hours is acceptable as well. Ultimately, newborns shouldn’t sleep less than 11 hours per day.

Infants
Infants should sleep between 12 and 16 hours, including naps.

Toddlers
Toddlers should sleep between 11 and 14 hours each day, including naps. Toddlers shouldn’t sleep less than 9 hours per day.

Preschoolers
Preschoolers should sleep between 10 and 13 hours per day, including naps.

Children (6-12 years of age)
Children should get 9 to 12 hours of sleep.

Teens (13-18 years of age)
Teens should get 8 to 10 hours of sleep per day.

Adults (18-60 years of age)
Young adults should get 7 to 9 hours of sleep per day.

Older Adults (61-64 years of age)
Older should get 7 to 9 hours of sleep per day.

Seniors (65 years of age and older)
Seniors should get at least 7 to 8 hours of sleep each night.

Is 6 Hours of Sleep Enough for You?

While 6 hours of sleep isn’t enough for most of us, there are signs you can watch for to determine if 6 hours of sleep is enough for you. For instance, yawning, fatigue, brain fog, and irritability are telltale signs that you’re simply not getting enough sleep.

Other symptoms of tiredness or sleep loss include a lack of motivation, clumsiness, and increased appetite. If you’re sleeping for six hours or less per night while experiencing these symptoms, you’ll need to increase the amount of sleep you’re getting to reflect nightly recommendations for your age, or you’ll need to find ways to improve upon your quality of sleep.

Did you know that Biostrap offers an advanced sleep tracking and analysis feature? In addition to the basic sleep offerings, the Biostrap Sleep Lab provides more frequent biometric recordings (up to every two minutes), plus after a 15-day baseline, you can get personalized sleep time and wake-up time recommendations to help optimize your circadian rhythm and achieve improved sleep quality and recovery. 

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Why Aren’t You Getting Enough Sleep?

Poor sleep or a lack of sleep can often be attributed to a number of factors. From taking sleep for granted to consuming caffeine before bed, sleep problems are widespread. Below you’ll find the common reasons people don’t get enough sleep.

Stimulants

Stimulants such as caffeine, alcohol, and even sleeping pills can interfere with your ability to fall asleep and stay asleep. While substances like alcohol may evoke the feeling of sleepiness, in reality, your sleep will be very restless. Sleeping medications, on the other hand, may be okay to use occasionally, but these become less impactful over time, and you may become dependent on them to fall asleep.

Shift Work

Those who work changing shifts have a more difficult time establishing a consistent sleep-wake pattern. While some adjust to these changes better than others, shift work can influence your circadian rhythm and drastically reduce the amount of sleep you should be getting each night.

Eating & Drinking Late

Eating late may impact the quality of your sleep. Going to bed on a full stomach will not only keep your body busy digesting what you just ate, instead of focusing on sleeping, but as elevated blood sugar levels trigger an insulin response, it can also cause a spike in cortisol which will keep you from transitioning into the sleep stages mentioned above.

Not to mention, certain unhealthy food choices may even cause heartburn, chest discomfort or bloating that may keep you up at night.

As a result, it’s best to avoid any late night snacks before bedtime. If you’re hungry, eat something small, such as a teaspoon of nut butter, and drink a glass of water or a cup of tea. 

Stress

Stress may keep us up at night and disrupt our sleep schedule. Elevated stress levels may keep your fight-or-flight, or sympathetic nervous system, activated, blocking your chance to tap into the parasympathetic, rest-and-digest, nervous system and get a restful sleep. Give yourself a chance to relax and unwind before bed — meditate, journal or do some breathwork — to help your body wind down. If stress is still stopping you from getting quality sleep, speak with your doctor to find techniques for coping with stress.

Sleep Disorders

​Sleep disorders are one of the most common reasons we suffer from sleep deprivation. Sleep apnea, night terrors, insomnia, and more can influence our sleep habits for days or even years at a time. If you suffer from a chronic sleep disorder that stops you from getting a good night’s sleep, consider talking to your doctor to determine what you can do to get back to bed.

Healthy Habits to Develop

Our body’s circadian rhythm is always telling us when it’s time to sleep and when it’s time to wake up. When this internal rhythm is disrupted, however, we’re left with a myriad of negative consequences leading to poor sleep. With this in mind, here are some tips on how to improve your sleep patterns so that falling asleep becomes a breeze.

Follow a Sleep Schedule

It may seem like a no-brainer, but your body prefers a sleep schedule that allows you to fall asleep and wake at the same time each day. This can also reduce your risk of heart disease, which sleep deprivation can increase your risk of developing.

Watch What You Eat

Avoid heavy meals close to bedtime and keep snacking to the minimum. Drinking water or tea before bed is healthy, but too much fluid can result in frequent bathroom trips that negatively impact your sleep duration.

Avoid Bedtime Distractions

Bedtime distractions such as digital screens, bright lights, and loud music can stop you from getting a good night’s sleep. Consider turning off your phone, dimming the lights, and reading a book before bed to allow your body and mind to wind down. A healthy bedtime routine that’s free of distractions will put your head in the right place before it hits the pillow.

Sleep Medicine

Though sleep medicine isn’t recommended for everyone, certain individuals may benefit from sleep medications that aid in falling asleep. If you find yourself suffering from a lack of sleep on a consistent basis, talk to your doctor to determine if sleep medicine is the right avenue for you.

So, Is Six Hours of Sleep Enough?

At the end of the day, six hours of sleep isn’t really enough for the average person. While we all know someone that functions well on less sleep, the side effects that come with a lack of sleep such as weight gain and compromised cognitive performance are reason enough to ensure you’re getting your recommended amount of sleep. While getting the sleep your body craves can be difficult, every hour of sleep you get makes an impact on your overall health.

Consider tracking your sleep with the most advanced digital health solution that’s available right now. Gain valuable insights into your sleep quality and start introducing a data-driven approach to understanding how your lifestyle choices are making an impact on your sleep and recovery.

Did we miss anything?

If you have any questions, suggestions or topic requests, please reach out.