Why do we need to Sleep - Why Sleep is Important

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". As well as humans, all mammals, reptiles, and birds also need to sleep but why do we need to sleep.

Even though the exact reasons why sleep is important 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 although several scientific theories have been put forward. 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.

Researchers have theorized that sleep may restore some chemical that is drained during periods of wakefulness. Scientists have isolated chemicals that vary during sleep, like adenosine, which affects metabolism and fatigue. However, no one has actually pinned down a definitive chemical explanation for sleep.

Some experts have speculated that sleep may be an evolutionary instrument to conserve energy whilst others say sleep may give the brain an opportunity to process experiences or even to exercise neural pathways that have lain dormant during the day.

Sleep has a healing effect in that it gives our bodies and minds time to rejuvenate, reenergize, and restore. We organize long-term memory, integrate new information, and repair and renew tissue, nerve cells and other chemicals. Sleep is also of an adaptive nature. As primitive humans and mammals, it was and is easier to find food during the day and, for mammals, to hide at night.

Sleep is also a matter of energy conservation. During sleep, humans are conserving energy when it would be unlikely to find food if we stayed awake.

A hormonal body clock also regulates sleep patterns. The melatonin in the body rises during evening hours which makes us sleepy. Morning brings a drop in melatonin concentration. Light also helps us stay awake. When human eyes get strong light waves, the melatonin production is depressed via links with our visual system. The amount and quality of sleep we get is directly related to the amount and quality of our productivity.

Not enough sleep can cause -