What is sleep? What happens while we're sleeping? Despite the fact that we're just laying there in bed like robots, things are always cooking behind the scenes. Let's take a quick look what exactly is going on during the night. After all, we dedicate a huge portion of our lives to it …
Sleep can be categorized into about four stages according to American Academy of Sleep Medicine which lumped together a couple of what used to be five stages back in 2007. Okay, it's a science … It's evolving. During the night we rotate through a complete sleep cycle several times until we finally awake the next day. Starting with stage one, progressing through stage 4 REM (Rapid Eye Movement) and then back again to stage two to start the cycle over. Stage one is usually skipped for the rest of the night.
The magic starts when your tired head hits the pillow with your eyes closed and your wondering thoughts begin tapering off into the distance. This is the first stage where you will find yourself drifting in and out of sleep. This stage is the lightest of them all and can be easily interrupted. It's a transitional period of slight unconsciousness which can be compared to a day dreaming experience. Those who practice meditation find themselves in a place similar to this first stage of sleep. Many of us do not actually realize that we're already there and if awakened would most likely not feel that we had been sleeping. The length of this stage is reliably quick, depending on the person and their surroundings and whatever interruptions you may face, typically around twenty minutes or so.
With the second stage, also lasting about twenty minutes or so, your eye movement slows to a stop. Your brain waves slow down while experiencing the occasional burst of rapid activity. Your breathing stabilizes and becomes more rhythmic as you become even more disengaged from your surroundings. Your heartbeat begins to slow slowly and your temperature also drops as your body prepares its own for the sunset of deeper sleep.
With the sunset of this third stage, the last of the non-REM's often lasting around forty minutes or longer, our brains experience deep slow waves know as Delta Waves and ever will experience these almost exclusively as the minutes progress. Your blood pressure will drop and breathing becomes slower. Your muscles become a bit relaxed while the blood supply to them increases. This deep sleep is the mostorative where growth hormones are released and tissue repair occurs.
Due to the deep level of sleep experienced in this stage, it is often particularly difficult to wake someone up during this time. Sleepwalking and bed-wetting will typically occur during this stage of sleep. Night Terrors can also occur at this time, not to be confused with nightmares which are distinctly different. A night terror is a sharp partial awakening that can result in behaviors such as thrashing or kicking, screaming or mumbling and rarely come with the recollection of these events the next day. To be fully satisfied, you will need to get several doses of the third stage, as this is often considered to be the most important.
STAGE 4 REM
This is the stage with the name that everyone's familiar with. REM which stands for Rapid Eye Movement, is just what sounds like, your eyes jerk and dart around quickly during this stage. Your breathing becomes irregular, shallow and more rapid. Your heart rate and blood pressure also increase. Unlike during the previous stages, your muscles typically do not move and your limbs become temporarily parsed. Your brain waves, however, increase to the levels of someone who is wide awake. REM sleep provides energy to your body and brain and has a direct impact on your daytime performance.
This dramatic increase in brain activity often leads to dreams or even nightmares, which we do not experience in any of the other stages. Although we may have a passing memory or image of something from one of the earlier stages, dreams only during REM sleep. Interestingly enough, the duration of your dream is usually relative to how long you seemed to have been dreaming. If you've had a long vivid dream, you probably were dreaming for a long time. As you rotate through your cycles as the night progresses, stage four will usually last a bit longer than the time before. From here we transition back to stage two to continue the cycle again.
Imagine what it would be like if you could never make it past the second stage … Millions of people suffering from Insomnia just can not fall into the cycle. What nightmare this must be.
Sweet dreams everyone!