As a start to our Sleep Month March 2021 our first article is some background about WHY we in fact Sleep and WHY it is so very important. Enjoy!
“Why Do We Sleep?”
We spend over a quarter of our lives asleep, yet it has only been really studied for the last few decades. We have known for many years that it is a critical function to support life but are now realizing just how much it impacts our overall health.
Sleep does not make a lot of sense from an evolutionary and survival perspective. You are unconscious, sometimes paralyzed, and completely unaware of any threats around you. Yet sleep has hung around as an evolutionary benefit since time immemorial and is common across every living animal in some shape or form.
Sleep really started to be studied in the 1950s, and William Dement was one of the founding fathers of the field. He founded the Sleep Research Center at Stanford University and was the first to record brain and eye activity through the night. One of the most relevant discoveries of that time was that sleep did have stages. While they were not quite sure what that meant, the leaders in the field were sure that sleep was not a monolithic state through the entire night. We know now about all 4 stages of sleep which include 2 stages of lighter sleep and 2 stages of deeper sleep.
Stage 1 sleep is simply your transition from wake to sleep, where Stage 2 is a light sleep that is the transition to your deeper stages. Stage 2 takes up approximately 50% of your night. We know these differences exist because your brain waves are distinctly different during each stage, in fact when the brain reaches Stage 2 sleep, we see a distinctive waveform called a K-Complex and these actually turn off your ears (probably why you don’t wake yourself with snoring). You can easily be woken during either Stage 1 or 2 sleep. Stage 3, sometimes called Delta sleep, is where we do an incredible amount of healing and regenerating. Without this stage, you will not feel refreshed and wakeful in the morning. Children spend a lot of time in this stage for growth and development, which you will have noticed if you ever picked up a sleeping child to move them to bed and they did not even stir.
Rapid Eye Movement (REM) sleep is the last stage in adults but the first stage in newborns. REM was often the first to be recognized in medicine due to its namesake eye movements that can be seen while you are sleeping in this stage. This is where we dream (80% of the time), and it is where our natural paralysis is supposed to keep us breathing but prevent us from acting out our dreams. This stage is vital for learning and creativity and can be thought of as the brain’s “filing system”. It will take new memories and try to connect them to old ones, and file them away in a location where it is linked to other memories so that we can find it again when we are awake.
Sleep was often studied in connection with psychiatry and psychology, and dreams were often “read” as a roadmap for our unconscious mind. We have now learned that dreams are vitally important, but not in the predictive way that many used to think.
We know that sleep impacts creativity, learning, decision making, immune health, vital organ function, healing, and emotional and mental health. We know that sleep deprivation will kill you faster than starvation. Matthew Walker PhD, the author of “Why We Sleep,” connects the importance of sleep to everyday health. For example, we know that withholding Rapid Eye Movement (REM) sleep severely impacts our ability to learn. Even a nap post-study session can significantly improve test scores later in the day. Studying the night before a test and getting a full night’s rest is even better, but if the REM sleep is removed from the sleep cycles then the results will be poorer.
Sleep is also foundational in our healing. This is the time our brain does repairs on the body and itself. Without sufficient deep sleep, we become incapable of keeping up with the list of repairs in our body. Poor sleep and some sleep disorders can also be detrimental to heart health by creating an environment of constant stress while we are sleeping. We often call these ailments just a part of “getting older” but this is more an outcome of a society that does not prioritize sleep as a medical necessity. As Dr. Muir always, says just because it’s common (snoring, sleep deprivation, fatigue) doesn’t make it normal and certainly not ideal.
The ability for our body to be self-regenerating in this way was such an advantage that it was justifiable to sacrifice 7-8 hours of our day as completely unproductive. By taking away our sleep health, it can lead to chronic mental and physical ailments that become worse over time. Now that we understand the importance of sleep, next week we will look at how we have landed ourselves in the middle of a poor sleep epidemic.
If you are interested in learning more about sleep, we highly recommend Matthew Walker’s book, “Why We Sleep.” He has also given numerous TED Talks, and our favorite “Sleep is Your Superpower” can be found at www.ted.com.