Scientific look into sleep deprivation

Sleep Disorders

Scientific findings about sleep deprivation

Sleep deprivation impairs a bunch of physiological functions, including immune regulation and metabolic control. Rats that are totally sleep deprived die after about 14 days, for reasons that are not clear. In the course of this deprivation rats show reliable and consistent changes. There is an initial body temperature rise, which then for a while returns to normal. The rats eat voraciously, but lose weight and develop malnutrition-like symptoms. The output of thyroid hormones falls, whereas catecholamines (adrenaline and noradrenaline) rise.

These changes are linked to the with eating and body weight. Animals develop peculiar necrotic skin lesions, and in the final stage of sleep deprivation body temperature drops and weight loss continues. By the time they die the rats have lost a lot of weight.

One of the first thing to change after a week of sleep deprivation in rats is an increase in food consumption and a drop in body temperature even as the rats attempt to keep themselves warmer. In humans, one of the first thing to happen, even after a single night of sleep deprivation, is a subjective feeling of cold. It is worth noting that during the REM stage of normal sleep, the body does not thermally regulate. (More on thermoregulation.) Objectively, scientists have determined that in human sleep deprivation the decline in body temperature is only 0.5° C. There is an increase in white blood cell counts and a general slowing of bodily functions.

Sleep and emotion interact as most psychiatric conditions are associated with sleep disroders. There are suggestions that the even mild sleep deprivation makes emotionally healthy people cranky.

Does sleep deprivation make you crazy? No. Not in a clinical sense does sleep deprivation lead to schizophrenia or mental illness. Visual misperceptions are common among overly sleepy people, but these are not hallucinations or waking dreams, as commonly believed, and auditory hallucinations do not occur in sleep deprived people any more than in rested people. (A recent - 2009 - article in New Scientist magazine suggests that bad sleep habits can indeed cause mental illness, or something like it. If this is true, sleep problems would be a cause, in addition to a symptom of mental illness.)

Some researchers think that even short-term sleep loss causes glucose intolerance in the body and hence has the same effect on the body as a pre-diabetes state.

A study published in the Journal of Neuroscience described the reversal in sleep deprivation effects in sleep-deprived monkeys by administration of the brain chemical orexin. Scientists gave the monkeys orexin by either injection to the blood stream or through a nasal stray. The monkeys' cognitive skills improved. It is not clear whether this will help lead to a treatment for humans.

Scientists have also found that flies with extra dopamine receptors can better withstand sleep deprivation.

One problem with sleep deprivation experiments is that the subjects are well protected, made comfortable, and at a low stress level, while real people with sleep deprivation undergo daily lives that may contain stress.