The duration of sleep and the body’s needs depend on the age and generally declines with aging. Newborns need to rest most of the day and usually sleep about 20 hours a day divided into periods of about 3 to 4 hours. Throughout childhood the rest requirements begin to decline and children just need to sleep between 10-12 hours. However, has been shown in studies that teen’s habits do not allow them to sleep the time that they need, increasing this way the level of daytime drowsiness. This phenomenon is due to many environmental and social factors that affect the body’s circadian rhythm and consequently the development and growth of the individual.
The sleep time needs of a young adult and middle-aged adult are the same in the duration, but there are some differences in the structure of sleep, i.e., the duration between REM and no REM phases.
Finally, the elderly sleep patterns alsol vary and are profoundly changed. A person often shows early signs of drowsiness at night and usually wakes up earlier in the morning. The dream of the elderly not very profound, which increases the likelihood of awakenings during the night, resulting in many cases the need for a nap during the day.
The causes responsible for the changes observed in sleep-wake cycles are not completely known. Melatonin, was established with a relationship between the production and the aging process. Melatonin is a hormone that acts as an indicator and regulator for the circadian cycle besides inducing sleep. It Has been showen that the aging process decreases the ability of melatonin synthesis which facilitates the onset of insomnia. This reduction in melatonin production is also responsible for the length and depth of sleep. These sleep disorders in seniors can have serious consequences. Indeed, lack of sleep can seriously affect mental and cognitive abilities of the individual, worsening the normal decline due to the aging process.