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How Much Sleep Do You Really Need?

The answer may surprise you.

Source: girl_onthe_les/Flickr

Recently I attended a retirement celebration for a longtime Physician colleague, Daniel Kripke, M.D., who was stepping away from his role with the Sleep Center at Scripps Clinic. Kripke is also a Professor Emeritus in the Department of Psychiatry at the UCSD School of Medicine.

As part of Dan's goodbye talk, he reminded us of the work that he had been doing in the area of sleep duration and that sleep is extraordinarily complex and multifactorial. This blog needs to be seen only as a way to introduce the notion of sleep duration to readers, challenge some of the thoroughly ingrained views about how much sleep a person really needs, and suggests how much we sleep is related to both health and mortality.

If I were to ask a random sample of adults, “How long do you think someone should sleep every night,” The answer in most cases, would be eight hours.

Eight hours, right or wrong?


The second question I would pose is, “Is sleeping too little, or sleeping too much associated with health risks?” The overwhelming response would be too little.

Too little, right or wrong?

Wrong again!

So, where do these beliefs come from, and how are they reinforced? Why do we believe that at least eight hours of sleep a night is so important—and in particular, that sleeping too little can have damaging effects? One reason is advertising. Almost every night, television commercials proclaim the consequences of not getting enough sleep and promoting the answer to this mythical, medical problem—take a pill, and if that doesn't work, take two!

What the ad does not say is that the effects of chronic use of the most popular prescribed sleeping pills are correlated with increased rates of mortality and drowsiness-induced increases in accidents.

Michael Dain/Flickr
Source: Michael Dain/Flickr

When one asks people how much they sleep, the answer is usually in the 7- to 9-hour range. However, if you actually track the amount of time that people sleep using an actigraph, most people sleep between six and a half and seven hours per night. Research supporting the need for at least eight hours of sleep per night does not exist.

Now, sleep is a very complex issue and there are a number of sleep disorders that have medical consequences including snoring, chronic insomnia, sleep apnea, restless leg syndrome (RLS), chronic fatigue disorder and narcolepsy. Sleep disorders can have major health consequences. However, we are also beginning to understand that the chronic use of medication to deal with occasional insomnia is a way of creating a problem rather than solving the primary one.

A combination of cognitive-behavioral therapy (CBT) and other nonpharmacological interventions have been shown to be as effective and possibly more effective than the use of sleep medication, (both prescribed, and over-the-counter variants) in treating occasional insomnia. Cognitive-behavioral therapy for sleep includes practices like relaxation exercises, stimulus control (i.e. keep televisions out of your bedroom, and don’t use your bed for purposes other than sleep and sex), and sleep hygiene education. The benefit of using CBT techniques over simply taking a pill is that CBT is able to get to the possible resolution of sleep issues, and there’s no risk of dependency. Some healthy sleep habits include:

  1. Don’t take long naps, and especially not late in the day.
  2. Make sure to allow in a little natural light in the early morning hours—this helps keep your sleep-wake cycle regulated.
  3. Don’t eat a heavy meal before bed.
  4. Create a relaxing routine and stick to it.
  5. Exercise early in the day.

Most researchers now believe that the relationship between sleep duration and mortality is best described as a U-shaped curve with the right side of the “U” considerably higher. That is, less than 5 1/2 hours of sleep is associated with some degree of increased mortality. However, sleeping beyond 9 or 10 hours per night is associated with a markedly increased mortality. The question, of course, is why. It has been hypothesized that if you’re very ill, you do tend to sleep a lot more and this increases mortality. That being said, it's not clear what this means. While older adults report that they sleep more, this may be because they generally measure their sleep staring with the time they go to bed rather than when they actually fall asleep. In older adults, too much sleep is associated with increased levels of cardiovascular disease.

Clint Gardner/Flickr
Source: Clint Gardner/Flickr

If you are having sleep-related problems (either sleeping more than 9 hours a night, sleeping less than 5 hours per night, having chronically disturbed sleep, or difficulty falling asleep), see your physician and, if appropriate, a sleep medicine specialist.

Treating the Numbers

By the same token, if you’re sleeping somewhere between six and a half and seven and a half hours a night, have not been told by a bed partner that your sleep pattern seems abnormal, and:

  • Most days you wake up feeling refreshed.
  • You are not usually sleepy during the day.
  • If you take an afternoon nap, it's usually for 20-30 minutes.
  • You are able to concentrate and do whatever work or retirement type activities you have chosen to do.
  • You are not depressed.

Then going to see your physician and requesting/demanding a prescription for a sleep medication, may mean that you are wanting to treat the numbers. There is no substantial evidence that you need eight hours of sleep a night.

So, go for a solid 6 or 7 hours of sleep per night, and stop worrying.

More from Morton H Shaevitz Ph.D., ABPP
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