sleep-needJust how much sleep is enough?

It’s every man for himself (and every woman for herself) when it comes to answering this question. Only you know how much sleep you need to feel rested and ready for the day.

But advice-givers for hundreds of years have offered prescriptions about how much sleep people need as if it were a matter of standard hygiene. Rinse your face when you get up in the morning. Brush your teeth twice a day. Wash your hands after using the toilet. Get 7 to 8 hours of sleep a night.

In reality, scientists have never found a way to determine how much sleep each person needs, so judgments about sleep need remain subjective. But there is quite a range in sleep ability, or how much sleep people report that they get.

What the Numbers Say

Sleep scientist Daniel Kripke analyzed a survey of over a million people and found that while a majority reported sleeping 7 or 8 hours a night, about 8 percent reported sleeping 9 hours or more, 16 percent reported sleeping about 6 hours, and 4 percent said they slept 5 hours or less. The best survival rate occurred for people who reported sleeping 6.5 to 7.4 hours a night.*

An average night’s sleep for me falls well below this, but I don’t worry too much about my mortality. I don’t care about the numbers as long as I wake up feeling pretty good.

Pronouncements About Sleep Need from the Past

  • “Much sleep ingendereth diseases and payne,” says The Schoole of Vertue in 1557, “It dulles the wyt and hurteth the brayne.”
  • “Nature requires five (hours), custom takes seven, laziness nine, and wickedness eleven.”
  • “Ten to 11 hours for children, 9 to 10 hours for women and feeble persons, and 6 to 7 hours for men,” says an eighteenth century book of devotions.
  • “For the healthy normal human being of sedentary occupation to … spend much more than a quarter of his time in sleep, is lazy neglect of his duty to himself and the race, and a reversion toward the stage of the amoeba,” says Dr. Fred W. Eastman in The Atlantic Monthly in 1911.

How much attention did people pay to pronouncements like these when they were delivered? Who knows. What I do know is that when claims about sleep need sound prescriptive, you’re better off taking them with a grain of salt.

* Mortality Associated with Sleep Duration and Insomnia

Posted by Lois Maharg, The Savvy Insomniac

Lois Maharg has worked with language for many years. She taught ESL, coauthored two textbooks, and then became a reporter, writing about health, education, government, Latino affairs, and food. Her lifelong struggle with insomnia and interest in investigative reporting motivated her to write a book, The Savvy Insomniac: A Personal Journey through Science to Better Sleep. She now freelances as an editor and copy writer at On the Mark Editing.

2 Comments

  1. Does disturbed sleep count for less? If I wake up every hour or two would I need more sleep time?

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  2. Hi Carol,

    These days the experts seem to put more emphasis on improving sleep continuity than on increasing total sleep time. They’ve had more success in helping people cut down on awakenings than in extending the time they sleep.

    Waking up every hour or two has to feel pretty lousy. If you wanted to improve your sleep continuity, you could try compressing your sleep to see that would get rid of the wake-ups. Go to bed later and get up earlier, and see if your sleep drive would build high enough to keep you sleeping through the night. People who go through cognitive-behavioral therapy for insomnia do something like this. I went through CBT, and it was helpful to me.

    The other thing to investigate would be medications for sleep maintenance insomnia. Silenor is the newest of these meds, which might be worth checking out with your doctor.

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