Circadian Sleep Essay

When most people think of sleep, they think of it as a relaxed but yet not a very important part of our daily lives. What most people don’t understand is although we are not up and moving around and getting tasks completed, our brains are still very active. Without sleep our bodies do not function correctly on a daily basis, and our mental state is at risk. Our bodies rely on two different things to let our bodies know when we need to be asleep. One is called the circadian rhythm, which is the physical, mental and behavioral changes that follow a twenty four hour cycle, that revolves around the light and dark of the day. Basically, our bodies are like our own little clocks which are controlled by a part of the brain called the suprachiasmatic

So for an average sleep time of eight to ten hours, we go through this sleep cycle four to five times a night. In stage one of the sleep phases, we are in a light sleep that lasts anywhere from five to ten minutes. In this stage, our eyes are still moving slowly and our muscles are slowing down, but may still have sudden muscle contractions like as if we were being startled or as if we were falling down. People in this phase may not feel rested if they are awakened, and might not of felt like they were even asleep at all. In stage two of the sleep cycle, you have successfully fallen into a light sleep. During this cycle your heart rate has slowed down, and your body temperature has dropped. You no longer have eye movement, and your body is finally resting the parts it has used through out the day. The next stage, which is stage three is also combined with stage four of the sleep cycle. These two cycles together are known as the delta sleep or the deep sleep stage, and is a very important part of the sleep cycle. During these cycles your body repairs and re-grows tissue, strengthens the immune system and builds bone and muscle. In these cycle it may be very hard to wake a person up, and if woken they may feel droggy or “out of it” for several minutes. In these stages is when most people have night terrors, experience sleep walking, or sleep talking occurs. In an adults average time of sleep this takes up about fifteen to twenty five percent of the time of sleep. Lastly, there is the REM cycle, which is also known as paradoxical sleep. During this cycle is when most of your muscles are paralyzed, your eyes are moving rapidly, and your breathing, heart rate and body temperature are not regulated. Vital signs show that during this stage, the arousal and oxygen levels