Why do we sleep?

Sleep facts - Why do we sleep?

We all sleep, but for scientists, the answer to the question “Why do we sleep?” is not clear-cut. The average person spends 36% of their life sleeping. That means that if you live to be 90, you will have spent 32 years sleeping. Those 32 years should surely tell us that sleep is quite important.

Sleep is defined as a period of inactivity and absence of waking consciousness, during which the body rests. Physical changes occur in the body during sleep: the muscles relax, and brain waves, heart rate, and breathing slow down.

The brain blocks most outside stimuli, lowering our consciousness, and shutting us off from the outside world. Therefore, the idea that sleep serves to restore the body and mind is logical, but probably not entirely true.

Both the brain and the body remain active during sleep, and the heart muscle doesn’t rest either. In fact, sleep—and especially REM sleep—consumes energy. Research has shown that there is a link between sleep deprivation and weight gain.

To really understand why sleep is so important to us, it is best to look at what happens when we don't sleep or sleep too little. Sleep deprivation negatively affects brain functioning. When you are sleep deprived, you remember poorly, are less creative and more impulsive, and have impaired judgment.

Lack of sleep weakens the immune system, which is why tired people are more susceptible to infections. In short: a good night’s sleep is the foundation of good health.

(source: Russel Foster, Why Do We Sleep)