How Much Sleep Is Enough?

While there's no magic formula that determines the perfect amount of sleep a person needs, everyone has an optimal level. Sleep allows the body and brain to recuperate, and not getting enough sleep can create serious problems, ranging from impaired motor skills to stress-disorders.

How Much is Enough?

There is no hard-and-fast rule on how much sleep the average person needs to function at a normal level, but there are general guidelines. As a rule, we need more sleep when we're growing, which is why babies, toddlers, children and teenagers require the most sleep. Once we reach adulthood, the amount of sleep we need plateaus around the eight-hour level that's long been considered the standard, but those requirements vary from person to person.

Benefits of Sleep

At it most basic level, sleep allows the brain and body to rest, recover and prepare for the next day. Sleep lowers blood pressure, slows the rate of energy consumption and gives the brain a chance to rest and repair neurons. Sleep patterns are controlled by the body's circadian rhythm, a 24-hour cycle that's developed in part by our own habits and routines. The most beneficial sleep occurs during Rapid Eye Movement (REM) sleep, which begins about 90 minutes into a sleep cycle and generates the most vivid dreams. The sleeping brain also sorts through experiences of the previous day and engages in a complex routine of reorganization that's still something of a mystery to neurologists.

Average sleep time

The younger you are, the more sleep you need. According to the Centers for Disease Control (CDC), newborns require up to 15 hours of sleep a day, but that number drops to 13 hours by age 2 and to 12 hours by age 3. Children typically require about 10 hours of sleep, and teenagers need an average of nine hours. For adults, eight hours of sleep has long been the norm, but that number can range from 6.5 hours to 9 hours. After thousands of years of conditioning, the human body and brain are programmed to go to sleep after dark and wake up when it's light.

Not Sleeping Enough

While getting too much sleep poses few problems beyond making us a little groggy, not getting enough sleep can create physical and psychological problems. A study from the University of California at Berkeley showed a severely sleep-deprived brain is incapable of making controlled, suitable responses to normal events and frequently shows signs of psychosis. A 2000 study published in the British Medical Journal showed that people who drove after being awake for 19 consecutive hours drove worse than people whose blood alcohol level made them legally drunk. Beyond impaired motor skills, not getting enough sleep for long periods of time has also been linked to obesity, depression and a variety of health problems typically associated with stress.

Healthy Sleeping Tips

There's no sure way to guarantee a good night's sleep, but the CDC offers several, common-sense tips for maintaining a healthy schedule.

Get to sleep around the same time every night and make your sleep environment cool and dark.

Avoid caffeine and alcohol before bedtime.

Exercise 20 to 30 minutes a day.

Avoid large meals and rigorous exercise before bedtime.

And if you can't get to sleep, don't lie in bed. Research has shown trying to force yourself to sleep has the opposite effect. Get up and do something until you feel ready to sleep.