Most people understand calories are essential for fueling the body. Circulation, digestion, and the conversion of food to fuel are all supported by daily caloric intake. What some people don’t know, however, is resting metabolic rate can make it easier to achieve weight maintenance and weight loss goals.
Some factors that influence resting metabolic rate (RMR), such as gender and age, are impossible to control. Still, other important factors are easier to influence. Here’s what you should know about resting metabolic heart rate and how it can be used to stay healthy.
What Is Resting Metabolic Rate?
You’ve probably heard a fast metabolism is helpful for weight management. But metabolism isn’t just about losing weight — it involves all the chemical reactions which keep your body alive. Rather than referring to your metabolism as fast or slow, it’s more accurate to refer to metabolism as being efficient or inefficient.
We can tell how efficient metabolism is by looking at resting metabolic rate. This is a metric used to determine the number of calories the body burns for basic functions. Specifically, resting metabolic rate focuses on what the body uses when it isn’t moving. It refers to the total energy used to keep your heart pumping, your lungs breathing, and your mind thinking. It doesn’t include energy expenditures required to engage in any kind of exercise.
A high resting metabolic rate means your metabolism is efficient, requiring more calories to achieve basic functions.
While RMR is often interchanged with basal metabolic rate (BMR), it isn’t exactly the same. While basal metabolic weight calculates the number of calories your body burns while at rest, RMR determines the amount of calories required for functioning at rest. Increasing your resting energy expenditure means you’re burning more calories at rest, which supports healthy weight management
Metabolism, Weight Maintenance, and Weight Loss
Resting metabolic rate influences healthy body weight maintenance. It helps you determine how many calories your body needs to function without putting on extra pounds. Any excess calories consumed beyond those used by RMR are stored as fat, which in turn causes weight gain. Calories lost beyond those needed to maintain weight may result in weight loss.
Knowing your RMR can help you create a healthy plan for weight maintenance, as it informs caloric needs on a daily basis. Still, RMR shouldn’t be your only metric when creating a weight-loss plan. Remember factors like age, body weight, genetics, and gender all influence your resting metabolic rate and ability to maintain or lose weight (more on these factors later). Moreover, different body types have varying muscle, fat mass, and therefore their own energy requirements.
How Do I Calculate RMR?
To calculate your resting metabolic heart rate, you’ll need to know your height and current weight. Then, depending on whether you’re male or female, you can use the following equations:
Female RMR = 655 + (4.35 × weight in pounds) + (4.7 × height in inches) – (4.7 × age in years)
Male RMR = 66 + (6.23 × weight in pounds) + (12.7 × height in inches) – (6.8 × age in years)
This number is how many calories you need to maintain weight. You can use this as a reference for how many calories you need to lose or gain weight.
Improving Your Resting Metabolic Rate
Increasing your RMR can help you burn more calories and achieve an ideal weight. But aside from shedding pounds, improving your resting metabolic rate can help you live healthier and longer.
People with higher RMR have more lean muscle on their body. This means that there’s a lower body fat percentage, which decreases the risk of heart disease, heart attack, diabetes, and high blood pressure.
Here’s what you can do to energize your metabolism and start burning more calories, faster.
Physical Activity to Boost RMR
As we’ve discussed, RMR is greatly influenced by daily activities. The number is also tied to your body composition, including your fat mass and fat-free mass (lean muscle). The more frequently you exercise, the more likely you’ll boost your metabolism and burn more calories. The types of exercises you do matter, too. For example, doctor and dietician Heather Klug suggests starting an exercise routine that slowly increases in intensity over time.
She said to try aerobic physical activity like running, swimming, or bicycling at least three times a week for half an hour. Try to make yourself breathe harder and perspire — this will indicate you’re operating above the moderate intensity level. As your body becomes accustomed to stronger workouts, raise the intensity level by going for longer or harder each week.
Promising studies suggest increasing intense physical activity can also reduce fat mass. In turn, this boosts the availability of lean muscle. Since lean muscle makes metabolism more efficient, reducing fat mass is a direct way to increase RMR.
HIIT and SIT
Another type of exercise that can increase RMR is HIIT, or high intensity interval training. HIIT workouts produce post-oxygen consumption. This means your body continues to burn calories long after you’ve finished the workout.
Switching up the intensities – rather than maintaining a consistent rate like you might when marathon running — ensures you keep burning fat for hours after your workout. This was proven in a study on Sprint Interval Training (SIT), where RMR increased with four weeks of sprinting workouts based off the HIIT model.
HIIT and SIT exercises also help you get more out of your workout with less time, said interval training expert Martin Gibala. “HIIT is an efficient strategy that offers the same amount typically associated with longer bouts of traditional cardio.”
Gibala and fellow researchers worked on a metabolic health study which shows working out at a high intensity for a shorter period of time is just as effective (if not more) than working out at a lower intensity for a longer time period. Specifically, sedentary men who engaged in traditional endurance training (like running) for 50 minutes increased their oxygen intake and overall heart health at the same rate as sedentary men who did HIIT for 10 minutes.
“The more aerobically fit you are, the better your heart can pump blood, the longer it takes you to get out of breath, and the farther and faster you’re able to bike or run or swim,” Gibala adds.
This makes your heart healthier, because it doesn’t have to work as hard to circulate blood through the body. The result? A reduction in resting metabolic rate.
Hormones, Age, and Metabolism
As mentioned, there are certain metabolic factors we can’t control. Gender is one of the major factors that influence metabolic rate, likely due to hormone distribution. For example, testosterone has an anabolic effect, meaning it supports increased muscle mass, said nutrition professor Douglas White.
Testosterone is also closely linked to body fat mass. Being overweight as a man may mean you have lower testosterone and increased estrogen, said researcher and nutritionist Atli Arnarson.
“First, belly fat contains high levels of the enzyme aromatase, which converts testosterone into estrogen, the female sex hormone,” Anarson said. “This explains why obese men have higher estrogen levels than normal-weight men.” Both aromatase and estrogen play a role in suppressing testosterone, which leads to decreased resting metabolic rate.
Age and Metabolism
You’ve likely heard that metabolism gets less efficient with age. This is also due to hormonal changes that influence how we store and lose fat, said Kristen F. Gradney, a nutritionist and spokesperson for the American Academy of Nutrition and Dietetics.
While metabolism efficiency slowly decreases between ages 30 and 40, lifestyle changes are typically the biggest culprit. The increased fat mass results when people sit more and workout less as they age.
“The best thing to do is to remain physically active, maintain muscle mass, and have a good diet. If you do those things, that progressive decline will be slower,” Gradney said. This shows that, regardless of inevitable hormonal changes, we still have some control over our metabolism.
Increasing Resting Metabolic Weight for Better Health
Resting metabolic weight is an important indicator of your metabolic efficiency overall health. Age, gender, and physical activity levels all influence a person’s calorie needs. Calculating your resting metabolic rate can help you create a metric-driven health plan that suits your specific caloric intake and energy balance needs. In turn, this can help you overcome predetermined metabolic factors such as age or gender to live a longer, healthier life.