How Much Sleep Do You Really Need?
Research Suggests That Sleep Requirements Vary From Person to Person
By Denise Mann
WebMD Health News
Reviewed by Laura J. Martin, MD


Nov. 30, 2010 -- Did you need an alarm clock to wake up this morning? If you did, you probably didn’t get enough sleep last night.

A new paper published by the National Sleep Foundation suggests that although there is no one-size-fits-all answer when it comes to how much sleep adults need, there are ways to tell if you are not getting sufficient sleep, such as a reliance on an alarm clock.

“We are all different,” says report author Michael H. Bonnet, PhD, a professor of neurology at Wright State University School of Medicine and the director of sleep laboratory at the Dayton Department of Veterans Affairs Medical Center, Ohio. “You need enough sleep so you can awaken feeling refreshed without an alarm clock.”

Some people need more sleep than others, he says. This need is based on genes, age, sex, and previous sleep amount, among other things. It also varies across the life cycle.
Sleep Deprivation and Health

Whether you need seven, eight, or even nine hours of sleep a night may be up for debate, but the importance of getting adequate sleep is not debatable. Sleep loss increases the risk of high blood pressure, inflammation, weight gain, and diseases associated with these risk factors, such as diabetes and heart disease. Sleep loss also impairs performance and mood, according to the report.

“It is in our society. It’s very easy to become significantly sleep deprived because we all have many priorities which seem to preclude or reduce sleep, such as work, school, or the Internet. We have information overload all the time, and that makes people believe that sleep is less important,” he says.

“The effects of sleep loss build up insidiously and results in decreased performance, poor mood, and health problems,” Bonnet says.

“The whole macho idea that ‘I don’t need to sleep’ is the same sort of macho fallacy that we applied to alcohol for a long time,” he says. “People were admired for being able to hold their liquor, and it was a matter of coming to the realization that drinking a lot of alcohol is not good for you and can cause significant medical problems and can be deadly.”

Sleep deprivation, too, can have deadly consequence such as falling asleep driving, Bonnet says.
Determining Your Sleep Needs

Michael Breus, PhD, author of Beauty Sleep and the clinical director of the sleep division for Arrowhead Health in Glendale, Ariz., says “there is still quite a bit of mystery to sleep and everybody’s sleep need is individualized and will change over the course of time.”

The key is to find out how much sleep you need to function, he says. “I don’t think there is one answer.”

Breus suggests this test to see how much sleep you need: If you need an alarm clock to wake, try going to sleep 15 minutes earlier. Do you still need an alarm clock? If you do, push your bedtime up another 15 minutes, he says. Do this until you no longer need an alarm to wake up. This exercise should give you a pretty good idea about the amount of sleep you need per night.

Another question to ask, Breus says, is how much coffee you are drinking. If you are pouring on the caffeine to stay awake, you are probably not getting enough sleep, he says.

If you get at least 7.5 hours of sleep a night and are not waking up feeling refreshed, see a sleep specialist, as there may be issues such as sleep apnea that are affecting your sleep quality, he says. Sleep apnea is marked by intermittent pauses in breathing during sleep.