What are the Fundamentals of Sleep?
Sleep deprivation is so common nowadays that not getting enough sleep seems like a given. But sleep is a very important part of our bodies health, fitness, and rejuvenation, and sleep deprivation can lead to many serious health problems.
What is sleep?
Sleep is defined as a naturally recurring state that is easily reversible. It is an automatic process, like breathing. Sleep is universal, and it has been observed in all mammals, all birds, and many reptiles, amphibians, and fish. When you sleep, you have reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles — all signs of rest and rejuvenation of their bodies.
Why is sleep important?
Sleep is a time of physical restoration, memory organization, and growth — a sort of mental “cleanup” for our bodies. Additionally, sleep is a time of rejuvenation of the immune, nervous, skeletal, and muscular systems. So sleep contributes a lot to our overall health and fitness.
Unsurprisingly, sleep deprivation can lead to startling effects on our health. When you get less than 7 hours of sleep a night, you are at a three times greater risk for catching colds compared to 8+ hours sleep. Sleeping less than 4 hours per night turns healthy adults into pre-diabetics. Long-term sleep deprivation can lead to serious health consequences, such as strokes, coronary heart disease, diabetes, cardiovascular morbidity, and even early mortality.
Outside of these serious health risks, sleep deprivation affects our work and productivity. Spending 16.9 to 18.6 hours awake is the equivalent of having a 0.05% Blood Alcohol Equivalent (BAC) while spending 17.7 to 19.7 hours awake is the same as having a 0.1% BAC. The legal limit to drive is 0.08% BAC, which means driving after 18 hours awake has similar effects as driving drunk.
What constitutes a good night of sleep?
There are 4 main phases of sleep:
- Wake (~5% of the night): Everybody has moments during the night when they wake up. Most of the time, these waking period are short and forgettable, but sometimes having too many waking moments can interrupt your rest.
- REM (~20% of the night): This is when you tend to dream. You tend to have very high brain activity during this time.
- Light Sleep (~55% of the night): This is the bulk of our sleep time. Your body is relaxed, there is very little brain activity, and it is easy to wake up. This is the ideal time in your sleep cycle to wake up feeling refreshed.
- Deep Sleep (~20% of the night): This is the time when our minds and bodies get rejuvenated. Your body is relaxed, and it is very hard to wake up from this stage of sleep.
You cycle through all 4 stages of sleep multiple times throughout the night. Each sleep cycle lasts about 90 minutes, and there tends to be more deep sleep at the beginning of the night and more REM sleep towards the end of the night. Ideally, after around 8 hours of sleep, you will wake up feeling refreshed in both your body and mind.
How can I sleep better?
There are three physiological systems that need to be perfectly aligned for you to fall asleep quickly:
First, you need to be sleepy. The longer you are awake during the day, the more “sleep drive” builds up in the brain. If you have a long nap in the afternoon or evening, it may be a little more difficult to fall asleep fast.
Second, your biological clock has to be synchronized with your bedtime. So, if you’re a bit of a night-owl, it will be easier to fall asleep fast if you go to bed on the later side. Conversely, if you are an early bird, you will find it easier to sleep earlier in the evening.
Third, your mind needs to be very calm, and your body relaxed! If you are feeling stressed about your day or anxious about falling asleep, your Fight or Flight system may get activated, which makes falling asleep fast near impossible.
All three systems need to be fully functional and in sync in order to ensure you fall asleep quickly and stay asleep throughout the night. Ironically, reminding yourself that you cannot force yourself to fall asleep is the first step in falling asleep fast.
Sleep is a crucial part of our lives and contributes greatly to our health, fitness, and overall lifestyle. Understanding how sleep plays a role in our lives contributes to how we can create a better sleep-life balance for fuller, richer lives.