What is the current research or prominent theories on why we need sleep?

This is from an article on MSNBC :

“Think of the body as a car. No car can keep going and going and going without a tune-up or oil change. If it’s not tuned, the car may keep running, but not as smoothly as it did when it was maintained properly. You can think of sleep as your body’s daily tune-up.

Human beings can function without a full tune-up, but they will be in a state of relative sleep deprivation and won’t be able to work or to think as well as they do when they are fully rested. It’s like an engine that gets only four out of eight spark plugs replaced and then runs sluggishly.

Sleep is also a time for restoring mental energy. We spend all day thinking and creating, and that uses up our energy stores.”

Whilst in REM sleep the brain produces Serotonin. Humans who go for extended periods without Serotonin slip into a psychotic state. Therefore, without sleep, we’d all be psychotic. REM sleep is the only time we produce Serotonin…. (unless you’re regularly subjected to Alpha waves.)

Sleep seems to be important so that our nervous systems can work correctly. If we do not sleep enough we feel drowsy and can not concentrate on what we do, we also experience impaired memory and physical performance and we are less able to carry out math calculations. If sleep deprivation is prolonged, we experience hallucinations and mood swings. Doctors and scientist say that, with enough sleep, used neurons have an opportunity to repair themselves, so if we don’t sleep properly these neurons become so depleted in energy that they can malfunction.

Check this too. . .The importance of Sleep

“Most scientists agree that one of the major purposes of sleep is to restore and heal the body. It has been observed that hormone and immune functions change during specific stages of the sleep cycle. Furthermore, some studies have shown that sleep deprivation can lead to deficiencies in the immune system. ”

“It has also been hypothesized that sleep offers important restoration to the brain. It is possible that neurons are restored, that brain proteins and certain hormones are produced. Some scientists believe that sleep is particularly important to the brains in young humans. Sleep deprivation in early life has led to decreased brain mass, permanent sleeping trouble, and behavioral problems. Although many scientists feel that the main function of sleep is not to restore or improve the capabilities of our memory, it has been observed that people have an easier time memorizing information if they have had adequate sleep than if they are sleep deprived.”

“A completely alternate theory to those described above is the “Preservation and Protection” theory of sleep. This theory asserts that human beings do not require the full 24 hour period within each day to satisfy basic needs such as collecting necessary food and supplies, eating, and reproducing. As not all 24 hours are required, sleep offers a time of rest when humans are not out in the elements, and therefore exposed to threats.”

Source

Because you will go insane without it. Sleep deprivation is a tried and true method of torture.

Sleep deprivation would result in a nation entirely populated by Dan Quayle clones.Shudder to think.

I have been awake almost continuously since 7:30 yesterday morning, and I am achey all over, especially in my arms. And my head hurts…one more midterm to go…
Sand butt paper basket armadillo mold face

i currently came to the conclusion that the lack of sleep is the root of all evil. if you have a truly restful nights sleep, you wake up and can do anything! It’s marvelous.

This is coming from an incredibly sleep deprived individual who typically gets anywhere from 3–5 hours of sleep per night. Once I reach that 7th or 8th hour…I wake up in love with everyone. Like my neuro-system can’t handle it. Sensory overload.

@Cloverfield I looked around for proof of “we produce serotonin – and only during REM”.
No such thing. There is serotonergic pathway activation using serotonin, but serotonin is not produced then – I don’t think. Neither does the head of biopsych here. Agreed with the rest of the answer.

Recharge at all levels