Why We Sleep

by Kaleb Montgomery, Doctor of Traditional Chinese Medicine

Sleep is a wonderful thing. Unfortunately for many of us a good nights sleep is something that happens all too infrequently. The question I will explore today is why we sleep.

The most obvious answer as to why we sleep is to recover and heal. The body needs to repair itself, clean out waste products and replenish energy stores. Waking up feeling rested is one of life’s simple pleasures. However this physical recuperation is only one of the many functions of sleep.

When we sleep we go through 2 main phases. The first phase is when our body and our minds are both at rest. This part happens shortly after we first fall asleep. It is brought on by reduced sensory input. (darkness, quiet, no movement etc.) The function of this part of sleep is the restorative one mentioned above.

The second phase of sleep is called Rapid Eye Movement or REM sleep. This is the part of sleep were we dream. It is called Rapid Eye Movement because of the movement of our eyeballs underneath our eyelids that happens when we dream. This part of sleep is not necessarily restful. Our mind is acting like it is awake during REM. Our body can react too. Sleep walking, talking in our sleep and tossing and turning in response to a dream all happen during REM as well. We cycle through these two phases of sleep throughout the night. As the night progresses we have less “restful” sleep and more REM sleep. So why do we have REM sleep if it is not restful?

There are many functions of REM sleep. One function is to help with memory and learning. Research in rats suggests that we repeat things we have done in the day again during REM sleep. This repeating of newly learned things during REM looks like it could be a key step in our learning process.

Another function of REM is in processing the emotional stress we experience during the day. Our dreams express our fears, anxieties and frustrations. Here our dreams act like a release valve, blowing off the accumulated steam of the day. This is a critical function for our survival. In a set of Machiavellian experiments with rats it was discovered that if you deprive rats of any sleep, they die after about 3 weeks. If you allow them to have the first “restful” phase of sleep but not REM sleep they die after 5 weeks. Seeing these results opened my eyes to other possible functions to sleep besides physical resting and restoring.

Through the rat sleep deprivation experiment I noticed how critical REM sleep and dreaming is to our survival. The rats died quickly even when they were allowed to have the first “restful” portion of sleep. This illustrated that without the nightly processing and stress release of REM sleep life quickly becomes figuratively and literally unbearable.

Take a look at your own sleep habits. How often do you wake up feeling rested? Next time we will explore the subject of sleep some more. In the mean time give your friendly Doctor of Traditional Chinese Medicine a call if you need help sleeping better.