Sleep is a biological process that every person must experience every day in order to rest and renew for their mental and physical health. Its main purpose is to allow the body and brain to rest after a tiring daily life. When people start the day in a fit and rested state, it shows that they have had a healthy sleep process.

If the body could not get enough rest during this period and the person starts the day tired, sleep disorders should be suspected.  Disorders that cause people to experience various problems during the day due to not getting enough sleep and/or physiological events occurring during sleep are generally classified as "sleep disorders".