Anabolism is the phase of metabolism in which simple substances are synthesized into the complex materials of living tissue. Sleep is the fundamental anabolic process common to all life forms, plant and animal.
During sleep, the brain remains active, going through a number of well defined stages. In each stage sleep gets deeper as bodies gets more relaxed and brainwave patterns slow down.
Rapid eye movement (REM) is the lightest form of sleep. During this stage, the eyes move rapidly and the activity of the brain’s neurons is quite similar to that of waking hours. It is the stage with the most vivid dreams.
People usually have about four or five periods of REM during a night of sleep. These periods get longer as the night progresses. The total time of REM sleep per night is only about 90-120 minutes, although it may seem longer when dreams are unsettling.
People normally wake for a short time at the end of a REM phase.
A delta wave or delta rhythm is a large, slow brain wave associated with deep sleep.Delta sleep is the most physically relaxed stage of sleep.
The level of melatonin, a hormone and derivative of the amino acid tryptophan, is high at times when we tend to sleep. Normally, production of melatonin is stimulated by darkness and inhibited by light It helps regulate sleep-wake or circadian rhythms.
Chronic inability to fall asleep or remain asleep for an adequate length of time is called insomnia.
Insomniacs use various crutches to lure sleep into their beds–hypnosis, music, relaxation techniques, white noise and more–with various degrees of success. After a few trial-and-error attempts, most people determined to sleep, can find an aid to help them without resorting to drugs!