by SNorris

Created on: December 30, 2008

Life for many of us consists of work, school, family, social life and many unexpected events that occur throughout our daily lives, keeping us busy most of the day. How many times have you thought "there is just not enough time in the day to finish everything I need to get done"? How many times have you given up some or all of your much needed sleep to finish it all? Many of us would be more than happy if we did not have to sleep at all, but this is just not possible if we want to survive and be productive each day. Our bodies have an internal rhythm or clock known as the circadian clock which regulates the way our bodies work during the day. It is made up of a tiny bundle of neurons that release melatonin, the hormone that makes us drowsy, and it is responsible for making us alert during the daytime and sleepy at night. As more of this hormone is released we get drowsy and then drift off to sleep. In addition to melatonin being released to make us drowsy, the cortisol hormone level dips at bedtime and increases over the night to promote alertness in the morning.

Giving up sleep affects every aspect of our lives including how we look, feel and perform on a daily basis, and it can have a major impact on our overall quality of life. So, what actually happens when we sleep?

Scientists can recognize different stages in sleep by tracking the changes in the brain waves during sleep. The body cycles through five stages as many as five times each night while we are asleep, so the body is quite busy during this time. To get the best benefit, we need quality sleep and enough sleep to complete all of the necessary phases for muscle repair, memory consolidation and release of hormones regulating growth and appetite. If sleep is cut short, the body cannot complete all of these phases and we are less prepared to concentrate, make decisions or engage fully in school, work or social activities during the day.

Our sleep follows a pattern of alternating REM, rapid eye movement, and NREM, non-rapid eye movement, sleep throughout a typical night in a cycle that repeats itself about every 90 minutes. As the night progresses each cycle lengthens and REM sleep, in which most dreaming takes place, extends. During the first cycle, REM lasts about 10 minutes, and lengthens a little during each cycle until it lasts about an hour.

As we fall asleep we enter NREM, non-rapid eye movement sleep, which consumes about 75% of the night and is composed of four stages.

Stage One

During this stage we

• 1
• 2
• Next Page >>