3 ms·

This sounds like a gross oversimplification. For one thing - even if 90 minutes is the average length of a sleep cycle, this surely varies between humans. My sl

This sounds like a gross oversimplification. For one thing - even if 90 minutes is the average length of a sleep cycle, this surely varies between humans. My sleep cycle might easily be 80 minutes or 100 minutes long, rather than 90. If I were to use sleepyti.me, it might recommend that I go to bed at 11:00pm to get up at 6:30am. But if my sleep cycle is only 80 minutes long, it will be 40 minutes out in its recommendation, which means that I would wake up in the middle of a sleep cycle, rather than at end of one - exactly the opposite of what it's supposed to achieve! In addition, although the first sleep cycle averages 90 minutes, the second to fourth cycles are generally 100-120 minutes [1] which again throws off your calculations. In short, I'm extremely sceptical that such a simple rule could ever be effective for most people. [1] http://en.wikipedia.org/wiki/Sleep#Sleep_stages http://en.wikipedia.org/wiki/Sleep#Sleep_stages

ux-guru-12345 14y ago
Surely you are capable of subtracting the proper amount of time based on your personal cycle which may not be 90 minutes. You'd do best not to criticize the author for using the human average of 90 minutes when his audience is the average human.
tisme 14y ago
300,912 people apparently disagree. Sometimes even gross oversimplifications are better than nothing at all.
- qwertyboy 14y ago
  No, in this case it's actually not. Mathematically. See your parent for proof. And please do not bring the "a billion flies can't be wrong" argument into this.
- myndpage 14y ago
  That doesn't mean anything. You need a real study (placebo works great you know). crntaylor is right. The sleep stages differs a lot between individuals. You need to analyze brain waves in order to be more precise (you could also try to detect movements like the "Sleep as android" app on android. But that's far from perfect.)

ux-guru-12345 14y ago

Surely you are capable of subtracting the proper amount of time based on your personal cycle which may not be 90 minutes. You'd do best not to criticize the author for using the human average of 90 minutes when his audience is the average human.

tisme 14y ago

300,912 people apparently disagree. Sometimes even gross oversimplifications are better than nothing at all.

qwertyboy 14y ago
No, in this case it's actually not. Mathematically. See your parent for proof. And please do not bring the "a billion flies can't be wrong" argument into this.
myndpage 14y ago
That doesn't mean anything. You need a real study (placebo works great you know). crntaylor is right. The sleep stages differs a lot between individuals. You need to analyze brain waves in order to be more precise (you could also try to detect movements like the "Sleep as android" app on android. But that's far from perfect.)