Most of the time you don’t remember what you dream about. You also have no idea of what goes on in your body once you are asleep. There are some interesting and amazing things that happen in each stage of sleep:
The first stage of sleep happens between being awake and slumber. You can be awakened very easily in this stage of sleep. Your body is trying to relax and slip into that deep sleep. Your eyes will move back and forth and you may end up having what is called a hypnagogic jerk which is when your muscles twitch involuntarily. If you are woken up during this stage you may feel like you have gotten no rest at all.
The second stage is a deeper sleep in which your body temperature dips and you lose a sense of your surroundings. Your blood pressure decreases and your heart rate drops because your cardiovascular system needs its rest too. When you are in this stage your brain waves also slow down. You spend about half of your night in this stage of sleep.
The third stage is the deepest point of sleep. You cannot be easily awakened from it. Hormones are secreted during this stage. Your blood pressure is still low, your temperature is still low, and now your breathing is slowing down too. The blood in your body flows through the muscles and repairs any damage that may have been done during the day. This stage of sleep happens early in the night and is where you spend around 20% of your sleep cycle.
Finally you have the REM cycle. This is where your dreams come in. You may remember some of them, you may not. Your eyes are quickly darting back and forth in your head which is where REM (rapid eye movement) comes from. One of the most interesting parts about the REM cycle is that your muscle groups become paralyzed. This is so that you do not act out your dreams. You spend 20% of your time in REM but most of it usually happens towards the end of the night.
Some of the other things that happen with our bodies when we are sleeping that don’t happen during a certain stage are:
– Appetite hormone ghrelin is suppressed
– Appetite suppressant leptin is released
– The brain flushes waste more actively during sleep