As you might know, there are four stages in the sleep cycle. The third phase is what people refer to as “deep sleep” or “slow wave sleep” (SWS) and it is part of the Non-Rapid eye movement phase(Non-Rem).
It is the most important stage in terms of body recovery and growth, and therefore especially crucial for younger people and athletes, when it comes to their their body development.
What happens during “Deep Sleep”?
As the name (Slow Wave Sleep) already suggests, the brain waves start to slow down. Compared to the two stages before, the heartbeat as well as the temperature decrease even further. By doing this the body reduces energy consumption, which then is utilized to grow and repair muscular tissues, as well as to release the human growth hormone (HGH).
During this stage, the body is very difficult to arouse, which means that you are less likely to wake up. The eye movement stops and the body enters a state of physical paralysis, in which only the life critical functions are maintained. It is extremely difficult to wake up during this stage and if it happens you might feel very sluggish afterwards.
However, it is a myth that we actually experience most of our dreams during the deep sleep stage. The majority of our dreams in fact happen during the REM sleep stage, in which we experience a very high brain activity.
Why is Deep Sleep so important?
Everybody knows the feeling: You get a good amount of sleep, but still do not feel well rested the next morning. This is because the body does a lot of its recovery and repair while in deep sleep.
Missing out on deep sleep not only negatively affects memory, growth, immune function and physical recovery, but research is showing that lack of deep sleep contributes to reduced insulin sensitivity, psychiatric disorders and insomnia.
So deep sleep is obviously very important for your general health, but how much of it do we really need?
Typically, deep sleep makes up 10-35% of your total sleep time. Most of the adults spend 10-25% per night in this stage. The percentage is influenced by different parameters such as your nutrition, your health, physical exercise during the day and the accumulated need for sleep of the night before. Another, important aspect that influences both the duration, as well as the importance of deep sleep, is your age.
Infants, children and teenagers spend significantly more time in this stage. But how much exactly and what is the main reason, for this difference?
The older we get, the more difficult it gets to reach the recommended amount of deep sleep, which is with 15-20% slightly less than the portion of REM sleep.
This is, because our body signalizes that it doesn’t need to set free the human growth hormone (HGH) any longer and therefore doesn’t recognize the value added of staying longer in this stage. Thus, older people often don’t recover slower than younger people, since they spend much less time in the “healing” sws stage. You might have noticed in your family that “older” people tend to sleep much less. This is not due to the fact, that they simply need less sleep but more due to pain, health problems and difficulties to maintain sleep. Another very common cause is incontinence, which makes people get up multiple times at night and therefore disrupts the sleep.
In contrast the sleep patterns of newborn childs differ a lot, as they need to set free a huge amount of HGH, blood cells, muscle fibers, and other important physiological building blocks. In fact, the entire sleep cycle of infants is different unique. When it comes to really young children and infants, science doesn’t divide in four different stages (drowsiness, light sleep, deep sleep, REM) but just in three:
- Active sleep
- Quiet sleep
- Intermediate sleep
During the active and quiet phase infants get a lot of deep sleep, which lasts several hours per night and gives them adequate rest and energy to grow.
In the midst of the puberty, at the age of around 15, slow-wave sleep is still crucial for growth, but hormone shifts and the body changing in general often disrupts and changes sleep patterns.
Overt time the sleep cycle develops into the one of adults, which consists of the “four stages”, since less HGH is needed. Therefore, more and more of the third sleep stage converts into the second sleep stage, until more or less 40% of a teenager’s third stage sleep is now an adults second stage sleep.
What happens with a lack of deep sleep?
As you know now, the stage of deep sleep is all about the body. Therefore, a lack of such hinders the body to “heal himself” and set free the appropriate amount of HGH.
People who suffer from chronic illnesses have an even more important need for deep sleep, since it helps them to repair caused damages and build replacement tissues (e.g. skin cells, bone cells).
Deep sleep is especially important during childhood and a lack of such has strong consequences. Children consistently deprived of deep sleep fail to set free an adequate amount of growth hormones – leading to underdeveloped limbs and an overall weaker physique. Therefore especially children need plenty of deep sleep.
How to increase deep sleep
- Establish a sleep routine
If you don’t have a good sleep routine to begin with, it doesn’t make any sense trying to increase your deep sleep with medication, biohacks or other sleep enhancers.
Your sleep routine should focus on things such as nutrition, prioritization of sleep, creating a good sleep environment and consistency. Once you’ve established a healthy sleep routine, you will see the positive effects of it not only to deep sleep, but other stages of the sleep cycle.
- Limit your caffeine intake
This one should be pretty obvious, yet many people forget how important it is for a good night sleep. It is well known, that caffeine stimulates the body and helps to stay awake and feel more energized. This leads to difficulties falling asleep, when you consume too much.
If you are looking to increase the duration of deep sleep each night, try to avoid caffeine during the day. If this isn’t an option, have it first thing in the morning.
Caffeine has a long half life, meaning a cup of coffee at 3pm will affect your body even in the evening.
In addition, most people increase their caffeine intake, when they start to feel tired. Which leads to a bad sleep at night and even more caffeine the next day. So limit the amount of caffeine every day to avoid entering this doom loop.
- Avoid stress
Even with a solid night time routine and the perfect diet, stress will always hinder you from entering a healthy deep sleep. The amount of stress, pre sleep, is directly associated with a reduction of SWS. So the assumption, that falling asleep will simply wash away the stress is wrong. The damage that stress causes to your body is already done even before you even start sleeping.
If you really want to increase your deep sleep, you should be serious about stress control.
- Have sex
To convince you giving this one a try probably won’t be very difficult, but in fact having an orgasm can heavily increase your sleep quality, due to sedative effects.
However, this really varies for each person, but if you are one of these people that experience those sedative effects this might be the easiest step in this article. Just have sex before you want to sleep. It’s as simple as that.
While having sex your body releases a lot of different chemicals, of which some can have positive effects on your sleep quality.
- Avoid physical activity before sleep
Physical activities are a sort of stress for your body. So again, even if you don’t even feel stressed, your body does and this is all that matters. By working out immediately before going to bed your blood pressure rises, which makes it more difficult for your body to enter a state of drowsiness. Of course physical activity is very healthy and also a must for a good night’s sleep, but try to focus doing sports at the beginning of the day.