by Dr. Jerry Kennard

Created on: May 06, 2010

Why to we spend so much of our time sleeping? Is it a waste of valuable time or do we really need it? One way of finding out is to deprive a person of sleep and watch what happens.

Our bodies are tied in to a 24 hour sleep-wake schedule. This ‘circadian rhythm’ involves an intricate series of activities involving temperature change, endocrine changes and secretion of hormones. The body clock is regulated by a tiny cluster of cells known as the suprachiasmatic nuclei, located in the hypothalamus region of the brain. Light signals from the optic nerve pass through the nuclei and this in turn regulates the production of the hormone melatonin. Darkness has the effect of releasing melatonin into the bloodstream and this reduces body temperature. So what exactly happens to a person when we interfere with sleep?

Sleep deprivation is something most people have experienced to some extent, but usually not extending beyond 24-48 hours. In sleep laboratories, the effects of sleep deprivation can be carefully monitored and studied. By following the typical adult we now know what the effects of a week without sleep are. It goes like this (adapted from Huber-Weidman, 1976):

The first night without sleep is comparatively easy. In the small hours of the morning the typical adult may find themselves feeling a little cold as their body temperature drops and they may find it difficult to stay awake unless they have a distraction of some sort. At worst the experience of a night without sleep is a sense of discomfort.

During the second night of sleep deprivation the desire to sleep is much stronger. The wish to go to sleep is worse between the hours of 3-5 a.m. when the body temperature is at its lowest. The person may feel headaches and become more tetchy in mood.

By the third night anything that requires sustained attention and mental calculations become seriously impaired. This is particularly the case if the task is repetitious and boring. Again, the early hours of the morning are the worst for wanting to go to sleep.

From night four onwards, periods of micro-sleep occur. People stop what they are doing and seem to stare into space for up to three seconds. The end of micro-sleep is accompanied by a return to full awareness. Confusion, irritability and misperceptions occur.

From night four, something known as the ‘hatband’ phenomenon is seen. The person complains of a tightening around the head as though a hat too small for the head is being worn.

Night five brings about additional effects. Delusions may be observed, although intellectual and problem solving skills are still functioning, albeit at a reduced capacity.

By night six of sleep deprivation the person begins to show serious signs of psychological discomfort. Symptoms of depersonalization occur and a clear sense of identity is lost. This is called sleep deprivation psychosis.

During periods of sleep deprivation the person may experience tremors, problems with focusing their eyes, a heightened sensitivity to pain and of course drooping eye lids. In a normal healthy adult, heart rate, blood pressure and respiration appear not to be affected to any great extent. This suggests that the effect of sleep is to benefit us more psychologically than physically. We appear to have the capacity to catch up with sleep loss quite quickly. For example, a  person who is deprived of sleep for three nights can feel refreshed after just one good night of sleep.

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