We spend about 8 hours/day, 56 hours/week, 224 hours/month and 2,688 hours/year sleeping. For what reason do we devote nearly one third of our lives to sleep? And why do we sleep so much? Resting is only one reason why we sleep, and we sleep to learn and process information, too.

Accordingly, we need sleep so much that if we miss one night of sleep, our body tries to recover what was lost subsequent nights. Sleep is indispensable, without it, we feel weak and dull. Sleep emerges to be universal; every species has some kind of sleep.

To facilitate sleep understanding, we must become familiar with some common vocabulary in this field. By starting to explain a little bit about the brain could be helpful.
Sleep may be distinct as a state of natural unconsciousness from which a person can be aroused. In spite of the advances that have been made in related areas, sleep remains a complicated physiological entity that is not yet fully understood.

For many years sleep was thought to be a purely passive state. Today, however, sleep is known to be an active process and that the brain is actually quite busy for the duration of sleep.

Sleep is now known to influence both physical and mental health, and is essential for the normal functioning of all the systems of the body. Ever since the body is known to require sleep as part of its homeostatic regulatory and repair mechanisms, it seems logical that the body can exert considerable influence on the sleep process.