One theory for why we sleep is the restorative theory. According to the theory, NREM sleep is key to reinstate physiological function while REM sleep is key for reinstating mental functions. The evidence to reinforce this claim is that the duration of REM sleep rises after tiring physical activity and sleep deprivation. Also, throughout sleep rates of protein combination and cell separation increase which advances the theory of restoration. A study in an October 2013 issue of Science suggested, “The restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.” What this suggests is that the brain uses sleep to clean out the body of waste toxins. This system is known as the glymphatic system. Due to the brain’s minimal ability, it must choose between cleaning up and sleeping or being awake and observant. Because of this, difficulties cleaning out the brain of waste may play a role in some brain disorders like Alzheimer’s …show more content…
This theory proposes that one of the main causes of sleep is to reduce energy consumption. This is theorized because energy metabolism is decreased during sleep. The rate at which the metabolism declines is around fifteen percent. Temperature of the body and caloric requirements reduce during sleep compared to wakefulness. This verification supports the claim that one of the reasons why we sleep is to assist organisms to reserve their energy resources. One claim against the energy conservation theory is explained by Russel Foster: “You essentially sleep to save calories. Now, when you do the sums, though, it doesn’t really pan out. If you compare an individual who has slept at night, or stayed awake and hasn’t moved very much, the energy saving of sleeping is about 110 calories a night. Now, that’s the equivalent of a hot dog bun. Now, I would say that a hot dog bun is kind of a meager return for such a complicated and demanding behavior as sleep. So I’m less convinced by the energy conservation idea.” The claim that the energy conservation theory is the primary reason for why we sleep may not be true, however it may play a role during