Why do we sleep, and how much sleep is necessary?

Why do we sleep, and how  much  sleep is necessary?

Sleep is a requirement for normal human functioning, although surprisingly, we don’t know exactly why. It is reasonable to expect that our bodies would require a tranquil ‘rest and relaxation’ period to revitalize themselves, and experiments with rats show that total sleep deprivation results in death.

But why?

First explanation;

It is based on evolutionary perspective. It suggests that sleep permitted our ancestors to conserve energy at night, a time when food was relatively hard to come by. Consequently, they were better able to forage for food when the sun is up.

Second explanation;

According to it sleep restores and replenishes or brains and bodies. For instance, the reduced activity of the brain during non-REM sleep may give neurons in the brain a chance to repair themselves. Furthermore, the onset of REM sleep stops the release of neurotransmitters called manoamines  and so permits receptor cells to get some necessary rest and to increase their sensitivity during period of wakefulness (McNamara, 2004;siegal, 2003; Steiger, 2007).

Final explanation;

Finally, sleep may be essential, because it assists physical growth and brain development in children. For example, the release of growth hormones is associated with deep sleep (Peterfi et al. 2010)

Still these explanations remain speculative, and there is no definitive answer as to why sleep is essential.

People who participate in sleep deprivation experiments, in which they are kept awake for stretches as long as 200 hours, show no lasting effects.

 It’s not fun they feel:

Ø     Weary and irritable,

Ø     Can’t concentrate,

Ø     Show a loss of creativity,

Ø     Even after only minor deprivation.

Ø     Feel edgy

Ø     Slow our reaction time

Ø     Lower our performance on academic and physical tasks

 There is also a decline in logical reasoning ability. However, after being allowed to sleep normally, they bounce back quickly and are able to perform at pre deprivation levels after just a few days (Babson et al., 2009; Mograss et al, .2009)

In short, as far as we know, most people suffer no permanent consequences of such temporary sleep deprivation. But –this is an important but --- a lack of sleep can also affect our normal functioning.

(Note)

The material provided in the post is taken from the book “UNDERSTANDING PSYCHOLOGY”   (10^th edition)

All credit goes to the author; Robert S. Feldman 

 (University of Massachusetts, Amherst)