Does Everyone Need Eight Hours of Sleep?

The world has tossed and turned for ages over how many hours of sleep a person really needs, but now it appears that the right answer might depend on the person.

A small number of people feel just as rested with 4 to 6 hours of sleep as those who require 8 hours of sleep.
A small number of people feel just as rested with 4 to 6 hours of sleep as those who require 8 hours of sleep.

The husband-and-wife team of neuroscientists Ying-hui Fu and Louis Ptáček have identified a genetic mutation that allows some people to feel completely rested with much less sleep than others. The couple, who work at the University of California, San Francisco, say these "short-sleepers" -- who number only about one in every four million people -- get just as much reward from four to six hours of sleep per night as those who require eight hours or more. And they don't need to catch up by sleeping longer on the weekend or taking naps.

On average, these rare sleepers grab 75 more waking hours per month than others. Fu said that understanding how these genes work might one day help everyone achieve better sleep, including those on the other side of the spectrum, who sleep 10 to 12 hours a night. "For me, it’s more interesting to help everybody sleep better,” she said.

Sleep on it:

  • Regular exercisers tend to fall asleep more quickly and get better quality sleep, but sporadic exercise can have the opposite effect, making it harder to nod off.

  • People who work in shifts are at a greater risk of several health issues, including cardiovascular disease, and their bodies never adjust to different sleep schedules.

  • Although there is no proof that going without sleep can eventually be fatal, the longest anyone has gone sleepless under observation is 11 days, 25 minutes.

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    • A small number of people feel just as rested with 4 to 6 hours of sleep as those who require 8 hours of sleep.
      A small number of people feel just as rested with 4 to 6 hours of sleep as those who require 8 hours of sleep.