Have you ever woken up feeling foggy, low energy, maybe even achy and craving all the sugars in the world? You likely didn’t get enough deep sleep. Slow-wave deep sleep, also known as stage 3 non-REM (NREM) sleep, is an important stage of sleep that is characterized by slow brain waves, reduced heart rate, blood pressure, and breathing rate, and relaxed muscles. This stage of sleep is essential for both physical and mental health, and getting enough of it is crucial for your recovery and overall well-being.
The amount of deep sleep you may get each night varies depending on factors such as the time of your last coffee, meal or workout, or even your stress levels. While you will go through several cycles of sleep during the night, it’s been found that you will spend more time in deep sleep during the first half of your sleep session. Then with each sleep cycle, deep sleep decreases. It’s exactly opposite to rapid eye movement (REM) sleep. You’ll spend less time in REM in the first half and more time closer to waking up.
In our blog about why tracking your sleep matters, we break down the different stages of sleep, so we highly recommend you to take a look for some additional details.
How do you know when to go to sleep?
There are two main systems that regulate your sleep: circadian rhythm and sleep homeostasis. You have heard us talk about circadian rhythm before, as it’s the environmental cues that control your sleep-wake cycle. As such, the sunrise triggers your body to release cortisol that helps you be alert, while sunsets and darkness impact melatonin release to help you sleep.
While the circadian rhythm, the body’s 24-hour internal clock, is impacted by external cues, sleep homeostasis is an internal regulatory mechanism, also known as sleep drive. It’s similar to your body telling you that you’re hungry and you should eat. The longer you stay awake the stronger the drive gets to make you sleepy.
The more consistent you are with your sleep schedule, the better quality sleep you’ll get each night as both your circadian rhythm and your sleep homeostasis will be in balance. The longer you adhere to that schedule and maintain that balance, the easier it will be for your body to develop a healthy sleep architecture with adequate time spent in all necessary sleep stages.
When will you get the most deep sleep
With a consistent sleep-wake cycle, your body will prepare itself to tap into deep sleep the first half of when you’re used to going to bed. Generally, going to bed before midnight and around 10 p.m. is most beneficial for getting the right amount of deep sleep.
However, if you are used to going to bed around 10 p.m. each night, but stay up on the weekend past midnight, you are stripping your body of most of this restorative phase of sleep. According to the Sleep Foundation, a few signs that you’re not getting enough deep sleep are:
- Feeling drowsy and not refreshed;
- Lack of alertness and attention;
- Having a hard time learning and forming new memories;
- Cravings for high-calorie food mostly sugars and simple carbohydrates.
Why it’s important to get enough slow-wave deep sleep
The physiological adaptations that occur during slow-wave deep sleep (SWS) help you to wake up refreshed, energized, and clear-headed, so you can perform your best that day. Take a look at below how SWS impacts your physical and mental health as well as mood and metabolism.
Physical Recovery
During SWS, the body undergoes a process of physical restoration and repair. This includes the release of growth hormones that stimulate the repair and regeneration of tissues, as well as the rebuilding of bone and muscle. It is also important for the immune system, as it promotes the production of cytokines – proteins that help the body fight infections, inflammation, and stress.
In addition, SWS helps the body conserve energy and replenish glycogen stores – the primary fuel source for muscles during physical activity. This is important for athletes and anyone who engages in regular physical activity.
Mental Recovery
During this stage of sleep, the brain organizes and processes the information that has been acquired during the day. This includes the consolidation of memories, the formation of new neural connections, and the pruning of unnecessary ones.
It’s been found that the glymphatic system that helps control the flow of cerebrospinal fluid, flushes out toxic molecules from the brain during SWS. These include beta-amyloids that are one of the main causes of cognitive disorders such as Alzheimer’s Disease and other dementias.
Studies have shown that SWS is particularly important for memory consolidation and learning. During this stage of sleep, the brain replays the neural activity that occurred during the day, which strengthens the connections between neurons and helps to consolidate memories.
Mood Regulation
Sleep plays a vital role in mood regulation, and SWS is no exception. Research has shown that sleep deprivation can lead to irritability, mood swings, and even depression. This is because SWS helps to regulate emotions, and the lack of it can disrupt the balance of neurotransmitters, such as GABA, dopamine, and serotonin that are responsible for mood regulation.
Energy Restoration
Finally, SWS is important for energy restoration. During this stage of sleep, the body conserves energy and replenishes glycogen stores. Additionally, it’s when the body rebalances your blood sugar levels. Studies have found that a lack of deep sleep may increase glucose levels and decrease insulin sensitivity.
Overall, slow-wave deep sleep is critical for physical and mental health. Getting enough of it is essential for our overall well-being, and a lack of it can lead to a range of health problems, including immune dysfunction, cognitive impairment, mood disorders, and even chronic diseases like obesity and diabetes.
As most of it occurs during the first couple of hours of your nightly slumber, make sure to stay consistent with when you go to bed and aim for shutting the lights off before midnight.
The best way to keep an eye on how much deep sleep you get each night is to track your sleep. The Biostrap Recover Set provides you with all the tools you need to gain valuable insights on your sleep quality and how much time you spend in each sleep stage. Additionally, utilizing AI and machine learning, our Sleep Lab feature will recommend the best bedtime and wake-up time for you to help you to recover optimally each day.
