About Apnea - Introduction to Sleep

Amounts of sleep vary significantly with age and even between individuals. Newborns sleep the most-a newborn baby sleeps between 17 and 18 hours a day, spending nearly half of that time in REM sleep. Both REM and NREM sleep decrease with age, and by age five, children sleep between 10 and 12 hours a day, spending about 20 percent of that time in REM sleep.

The average young adult seems to need about 8 hours of sleep per night to function optimally during waking hours. Some people, however, sleep just 6 or 7 hours a night, while others need more than 9 hours to feel rested. The elderly spend less time in deep NREM sleep, and their sleep is more easily interrupted.