Sleep is a naturally recurring state of mind and body, characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity and inhibition of nearly all voluntary muscles during rapid eye movement (REM) sleep.
Sleep is basically divided into two types: rapid eye movement sleep (REM) and nonrapid eye movement sleep (NREM).
Sleep is performed in the REM cycle and the four stages of NREM, sequences are usually as follows: stages 1> 2> 3> 4> 3> 2> REM. Each of these stages has different physiological, neurological, and psychological functions.
In addition, the National Sleep Foundation of the United States has previously recommended that eight to nine hours of sleep for adults is optimal and that adequate sleep is good for mental fitness, memory and problem solving, overall health, and also reduces the risk of accidents.
If you have trouble sleeping, seek the advice of a doctor and a specialist near you immediately. Do not let it deteriorate to affect your own health.
Sources: Public Health Malaysia