There are tons of articles, like this one, around the importance off sleep on health, fitness,etc. The one question i have is how do i know how much sleep i need. Most of these articles say between 7-8 hours but it depends.

If i only get 5 hours of sleep but still feel fine in the morning and don't see it impairing my activities, is that a problem. Are there still benefits that i am missing out on if i did sleep taht extra 2-3 hours?

  • I think the ultimate answer is going to be to lsiten to your body and know when it needs rest.
    – DForck42
    Oct 18, 2012 at 16:35
  • Not feeling tired doesn't mean that your body and mind aren't tired. Apr 25, 2013 at 2:52

2 Answers 2


To quote the National Institute of Health:

When healthy adults are given unlimited opportunity to sleep, they sleep on average between 8 and 8.5 hours a night. But sleep needs vary from person to person. Some people appear to need only about 7 hours to avoid problem sleepiness, whereas others need 9 or more hours of sleep.

So, you may in fact by an outlier that only needs 5 hours of sleep to be well rested and functional, but that is unlikely. Instead of considering how much sleep you need to "not have problems" consider how much sleep you need to "perform at optimal levels." So you may not be tired after 5 hours of sleep, but your cognitive abilities and physical abilities may (and likely are) affected by your current lack of sleep.


There is a difference between what is best for your health and what is realistic to implement in your life. The amount of sleep you need is different for everyone.

Ideally, it's best to go to bed when the sun sets (or little after) and wake up every day without an alarm clock. I did this for a month every day and felt amazing, but it does impact your social life. So I stopped doing it that extreme.

More realistic would be: get at least 7 hours of sleep during 'work days'. (7 hours is a good duration for most people. But you should experiment with this and find out what works for you.) Try to go to bed about the same time every 'work day'. On weekends, try to keep to this schedule as much as possible. And wake up without an alarm clock whenever you can.

Besides the duration of your sleep, there are a few other influences on the quality of your sleep. A few brief recommendations:

  • Sleep in a dark room, or with a sleeping mask
  • Only sleep (and do other bedroom activities) in your bedroom (don't use it for study/work)
  • Sleep in a quiet and safe environment
  • Write your worries down before you go to bed
  • Keep your bedroom clean and free of stuff that's just lying around
  • Keep your bedroom cool (use a warm blanket if cold)
  • Make sure your bedroom is well-ventilated
  • Where do you live that you can sleep at sun set ?! Sun set may occur at 4:30PM in Paris during winter !
    – Max
    Oct 26, 2012 at 17:21
  • @Max, are you saying that a person can't go to sleep at 4:30? May 1, 2013 at 5:26
  • @TannerSwett : not that you can't, I'm just saying that it doesn't seem realistic to recommend that on a "global scale" ; sunset time varies considerably according to your geographic location, that's all I'm saying.
    – Max
    May 1, 2013 at 18:09
  • until relatively recently the only source of light after sunset was a fire/ candle. Keeping that in mind I would think that humans evolved to sleep shortly after sunset until the crack of dawn. We screw up our rhythm with all these artificial lights. There's been some books written and research done on that but I don't have any of it handy. While it may seem outrageous jasper is probably right.
    – hortstu
    Jan 18, 2014 at 6:36

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