Have you ever heard the claims of some that they can go for ridiculously long amounts of time without sleep? Is it true? Well, it is possible that some individuals are able to function on dramatically less sleep than others. However, this is not the case for the vast majority of us. In fact, it is a sad part of our modern life that this vital aspect of our human condition is being adversely affected. Should we remain concerned? You betcha!

Humans must sleep. Studies have shown that people can live longer without food than they can without sleep. Shakespeare commented on the restorative nature of sleep calling it “nature’s soft nurse”. Mammals, reptiles, and birds also have to sleep.

Even though the exact reasons for sleep remain a mystery, we do know that during sleep many of the body’s major organ and regulatory systems continue to work actively. Some parts of the brain actually increase their activity dramatically, and the body produces more of certain hormones. No one knows exactly why we sleep but several scientific theories have been proposed. Some scientists have proposed that we may sleep out of mere habit, without any biological foundation. Sleep may be a time for the brain to recharge. During sleep, the brain shuts down and repairs neurons and exercises synapses that may slowly break down and weaken with a lack of activity. This could be a time for fine tuning the synaptic connections that get stronger, weaken, break and reform. Sleep, it is theorized, is a time to shift those synaptic connections back to their original design after they have been jumbled up during the day. Sleep gives the brain a chance to reorganize information to find answers to problems, to process new information, and to organize and archive memories. The brain reinforces memory and categorizes everything learned in a particular order, and erases the useless, impertinent information. During sleep, metabolism slows down as well as energy consumption.

Sleep may also be a time for rest for our heart and lungs. People with normal or high blood pressure have a 20-30% reduction in pressure and a 10-20% heart rate reduction. Sleep gives the body a chance to replace chemicals and repair muscles, other tissues and aging or dead cells. It may also have an effect on strengthening the immune system. In children and young adults, growth hormone is released during sleep. Circadian rhythm or a day-night cycle of about 24 hours has a large impact on the timing, amount, and quality of sleep. A stable circadian rhythm means better sleep. Adult humans need 7-8 hours of sleep per night. When humans sleep, the brain is able to filter events that do and do not have an impact on long-term memory. Brain glycogen levels are replenished during sleep. Sleep is necessary for survival in mammals. For example, rats will die after about two weeks without sleep. After significant weight loss, they will not be able to regulate their body temperature and will develop infections. A lack of sleep in humans leads to impaired memory and reduced cognitive abilities, mood swings, and hallucinations.

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