The dangers of sleep deprivation range from irritability to death. Just one night of sleep loss makes it difficult for people to make rational decisions and shortens attention spans. Sleep loss causes:
1.Mood Disorders. Chronic sleep deprivation results in mood disorders and depression. This is because sleep deprivation targets the prefrontal cortex of the brain which is responsible for emotions, memories and higher level cognitive function.
2.Cognitive Dysfunction. If a person is severely sleep deprived, he or she may experience micro-sleeps –brief periods of sleep while awake –without even knowing it. The motor skills and hand-eye coordination of sleep deprived individuals are as bad, if not worse, than intoxicated individuals.
3.Major traffic accidents. Fatigue, irritability and the decreased ability to concentrate lead to devastating vehicle accidents and workplace accidents. According to the National Highway Traffic Safety Administration in America, 100,000 crashes, 71,000 injuries, and 1,500 fatalities each year are the direct result of driver fatigue. Note that these figures are probably conservative and this estimate does not account for vehicle operators such as airline pilots, long-distance truckers, ship captains, and railway conductors. One can only imagine what the figures might be for Pakistani vehicle operators, if appropriate fail-safes and policy measures are not enforced.
4.Major medical and industrial accidents. Severe sleep deprivation in shift-workers performing vital tasks also gives rise to mistakes, accidents and catastrophes. Hospital workers and nurses are liable to make medical errors when working long shifts. Industrial workers too tend to make mistakes –the Chernobyl nuclear disaster, the space shuttle Challenger crash and the Exxon oil spill are in part attributed to sleep deprivation.
5. Heart disease. In the short term, sleep deprivation causes a surge in blood pressure and inflammation due to the rise of the stress hormone cortisol. Chronic sleep deprivation can therefore result in heart disease.
6. Immune system impairment. The immune system too is severely impaired by sleep deprivation. Studies with laboratory rats showed that rats deprived of sleep develop sores on their tails, the response of a damaged immune system, and die in a matter of weeks.
7. Diabetes. In the short term, sleep deprivation also causes impaired control of blood glucosedue to changes in the way insulin is secreted. Chronic sleep deprivation thus may result in obesity and diabetes
8. Obesity. Obesity may also occur due to the hormones leptin and gherlin. Leptin is released during sleep, and suppresses appetite. Gherlin is taken up during sleep, and increases appetite. Too little leptin and too much gherlin due to sleep loss can therefore cause obesity.
Sleepiness is caused by a very insistent and potent drive. One can voluntarily give up food and water until death, but the human body cannot force itself to stay awake indefinitely. Why? What happens inside us when we sleep?
1.Growth, maintenance, repair. The body starts to produce human growth hormone (HGH). A protein hormone, HGH promotes the growth, maintenance and repair of muscles and bones. Every tissue in the body is renewed faster during sleep than at any time when awake.
2.Maturation.Follicle stimulating hormone (FSH) and luteinizing hormone (LH), which are involved in maturation, are released during sleep. In fact, the sleep-dependent release of LH is considered to initiate puberty.
3.Weight regulation. Sleep regulates levels of the hormones ghrelin and leptin, which play a role in our feelings of hunger and fullness. So when we’re sleep deprived, we may feel the need to eat more, which can lead to weight gain.
4.Recuperation. NREM sleep is recuperative sleep – it increases after increased physical activity, and is given high priority after extended periods of being awake.
5. Memory consolidation. Regions of the brain involved in memory consolidation, such as the hippocampus, can be spontaneously reactivated during NREM sleep, especially when sleep is preceded by intensive learning. These activations may reinforce neural connections that help in optimizing daytime cognitive function.
6. Emotional processes. Brain activity increases in sensory areas. REM sleep is thought to help consolidate memory and emotion, as blood flow rises sharply in several brain areas linked to processing memories and emotional experiences.
7. Nervous System Development. Infants spend about 50% of their time sleeping in REM. This may aid the development of the Central Nervous System.
8. Immune system function. Researchers have deciphered the magnitude of sleep on the immune system by conducting studies on rats. Rats normally live over two years. Rats deprived of REM sleep live only for about 5 weeks, while those deprived of all sleep survive only about 3 weeks.