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← How much sleep do you really need?

You know you need to get enough sleep, but the question remains: How much is enough? Sleep scientist Matt Walker tells us the recommended amount for adults and explains why it's necessary for your long-term health.

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Showing Revision 5 created 08/27/2020 by Erin Gregory.

  1. So far, we've spoken about
  2. all of the wonderful
    benefits that sleep provides,
  3. but how much sleep should
    we actually be getting?
  4. [Sleeping with Science]

  5. (Music)

  6. For the average adult,
    the current recommendation

  7. is somewhere between seven to nine
    hours of sleep a night.
  8. And what we've been finding
    from large-scale epidemiological studies
  9. is that, using that reference point
    of seven to nine hours,
  10. once you start to drop below that,
  11. your mortality risk
    actually starts to increase.
  12. In fact, the Center for Disease Control
    in the United States, or the CDC,
  13. they stipulate a minimum
    of seven hours of sleep a night
  14. for the average adult.
  15. In other words, the shorter your sleep,
  16. the shorter your life.
  17. But it turns out that it's not quite
    a linear relationship as you would expect.

  18. It's not as though the more
    and more that you sleep,
  19. the lower and lower
    your mortality risk is.
  20. In fact, something strange happens.
  21. Once you get past nine hours,
  22. you actually start to see
    a rise back up in mortality risk,
  23. which seems rather strange and peculiar.
  24. And scientists have actually put forward
    at least two different explanations.
  25. The first is that,
    if you look at those studies,

  26. it may be that individuals are suffering
    from significant disease and illness.
  27. When we become infected,
    or we have disease,
  28. typically, we try to sleep longer,
    we stay in bed longer.
  29. So in other words,
  30. it was the unmeasured disease
    and sickness in those studies
  31. that was triggering
    a response in those individuals
  32. to try and sleep more.
  33. That's one explanation.
  34. The second possible explanation
    is poor sleep quality,

  35. because we know that sleep quality,
  36. independent of sleep quantity,
  37. is also associated with mortality risk.
  38. And the lower that your
    quality of sleep is,
  39. the higher your risk of death.
  40. People who have poor quality of sleep
    will typically try to sleep longer;

  41. they'll try to stay in bed longer
    to overcome that poor quality of sleep.
  42. It may be poor quality of sleep
    masquerading as long sleep
  43. that is associated
    with a higher risk of death,
  44. rather than the long sleep itself.
  45. But if we take a step back
    and think about society overall,

  46. I think modernity is constantly pushing us
  47. to, perhaps, work long hours
    and therefore neglect our sleep.
  48. But if we want to be around
    long enough to get the benefits
  49. and the fruits of all of that hard labor,
  50. we may want to think about starting
    to prioritize our sleep some more.