Get Some Rest
Written by Calvin Sun
(Originally Published March 15, 2010)
It seems to me that sleep has become an inconvenience in our lives. We are all so busy with endless lists of obligations to work, school, friends, family, and so much more. We have become a society of overworked, caffeine-addicted zombies. As a result, most of us don’t sleep enough. And it’s not just an issue of quantity, quality is affected in that many of us are also stressed to the point where we aren’t able to achieve adequate amounts of deep sleep.
Sleep is not simply a continuous state of unconsciousness, rather it is a physiological process that occurs in cycles of approximately 90 minutes. Each of these cycles can be broken down into five different stages. The first four stages are considered non-REM (Rapid Eye Movement) sleep and the fifth stage is known as REM sleep.
Stage 1
The first stage of sleep lasts about 5 to 10 minutes and varies between drowsiness and light sleep. Muscle activity slows down, although you may see some occasional muscle twitching. Most are easily awakened in this state and will not feel as if they have slept.
Stage 2
The second stage is a period of light sleep where respiration and heart rate slows. Body temperature will also decrease slightly during this period. EEG readings will show larger brain waves and occasional bursts of activity.
Stage 3
Stage 3 marks the beginning of deep sleep, it occurs approximately 30 to 45 minutes after the sleep cycle begins. The brain begins to produce slower, high-amplitude waves known as delta waves.
Stage 4
Stage 4 is a very deep sleep. It is characterized by delta waves and is also known as slow-wave sleep. Physiologically, breathing is more rhythmic and muscle activity is limited. If you are awakened during deep sleep, you will probably feel groggy, confused, disoriented and may be unable to function normally for up to half an hour.
Stage 5 – REM
As its name suggests, rapid movement of the eyes distinguishes REM sleep from other stages of sleep. Brain activity during REM sleep is similar to that during waking hours. Intense, vivid dreaming occurs during REM and most of the dreams you can recall occur during this stage. Studies suggest that REM sleep is essential for processing and consolidating emotions, memories and stress.
While every stage of sleep is important, stages 3 and 4 – or slow-wave sleep, seem to be of particular importance. Several studies have shown that when deprived of sleep, there is an increased amount of slow-wave sleep the following evening. Many neuroscientists have suggested that this indicates there is a physiological “need” for slow-wave sleep as it may be the most “restorative” form of sleep. Sleep is still not completely understood as there is an abundance of on-going research on the subject. We do, however, know that sleep is essential to your health as sleep deprivation can result in a variety of undesirable conditions.
Tomorrow we will review some of the various conditions associated with sleep deprivation, and will provide you with a few tips for improving your quality of sleep.