To Your Health August, 2012 (Vol. 06, Issue 08)

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Good Sleep Is Essential To Your Health

By Robert J Troell, MD, FACS

All animals require sleep. Sleep restores the body and the mind. Why do human beings sleep? All metabolic processes require restoration of their function, which is achieved through sleep. In 1834, MacNish stated: "Sleep is the intermediate state between wakefulness and death;" wakefulness being regarded as the active state of all the animal and intellectual functions and death as that of their total suspension.

Rodents die within about 21 days if completely sleep deprived and it is theorized that humans would die after about 180 days of sleep deprivation.

What are the stages of sleep?

As Dr. William Dement, the first physician board certified in sleep and founder of the Stanford University Sleep Disorders Center, stated: "The interest in sleep and dreams has existed since the dawn of history and perhaps only 'love' and 'human conflict' have received more attention from poets and writers." There are three distinct physiological states of the human body: awake, non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. The brain waves and the status of the neuromuscular system are different in each of these states. Alterations in the "normal" state of sleep has produced over 160 diagnosis of sleep pathology.

Non-REM Sleep

The awake state has a predominance of alpha activity as well as low voltage, mixed frequency pattern. Stage I sleep is the transition from the awake state to stage II sleep, shown by diminished or disappearance of alpha activity and a relatively low voltage, mixed frequency EEG pattern, often in the presence of slow-rolling eye movements. Stage II sleep has K-complexes and sleep spindles with a mixed frequency background. Slow wave sleep reveals high amplitude (>75 microvolts) delta waves with a frequency of 0.5 to 2 Hertz, that is between one-half to two seconds in duration. Delta sleep occurs more commonly in the first one third of the night and decreases with age.

REM Sleep

REM sleep is scored having three criteria: First, EEG returns to relatively low voltage, mixed frequency pattern with no K-complexes or sleep spindles. Some patients also reveal a "sawtooth" EEG pattern. Second, chin EMG decreases in amplitude to its lowest levels, and third, EOG reveals rapid eye movements. REM is more prominent in the last third of the night. Although one can dream in all stages of sleep, dreams in REM sleep are much more vivid and may have "phasic" body movements associated with them. This is commonly observed when one's dog is dreaming and chasing a feline friend with the extremities moving, the eyes fluttering and the dog barking or panting. REM sleep occurs 90-120 minutes after sleep onset and approximately every 90 minutes thereafter.

Sleep Disorders

One needs to understand normal sleep before under taking diagnosing and treating sleep disorders. There are four sections in the classification of sleep disorders:

1. Dyssomnias, which comprises disorders that cause a complaint of either insomnia or excessive sleepiness.
2. Parasomnias, which comprises disorders that intrude into or occur during sleep.
3. Medical and psychiatric disorders associated with sleep disturbance.
4. Proposed sleep disorders of new and rapid advances in sleep disorders, such as short and long sleepers and fragmentary myoclonus.