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Which sleep schedule results in more sleep debt?

Schedule 1:
Night 1: 8 hours
Night 2: 8 hours
Night 3: 8 Hours


Schedule 2:
Night 1: 6 hours
Night 2: 6 hours
Night 3: 12 hours
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up vote 2 down vote accepted

If this were a case of purely the maths then it would trivially be the second (because you'd have the debt for longer) - but the model is too simple, sleep depends on far too many factors to be reduced to this kind of calculation.

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Regardless, it is a good question to consider – Casebash Mar 22 '12 at 10:01

Using this website as the model, here are my calculations.


  • Max sleep debt is 20 hours.
  • Sleep required is 6 to 8 hours.
  • You can only pay back 2 hours of sleep per day.
  • Sleep can't be banked (sleeping extra when you have no sleep debt doesn't prevent sleep debt accumulation on the future days)

Lets assume that you need 8 hours of sleep (and the above model is very sensitive to the goal number, most websites advise 6 to 8, but don't provide any help in deciding if someone who sleeps 8 really only needs 6 but are lazy or vice versa.) In scenario 1 you have 0 sleep debt.

In scenario 2 you have 4 hours of sleep debt after two days, but you only pay down 2 hours on the third day (because you can't pay more than 2 hours of sleep debt per day). So the final sleep debt is two hours.

If you assume 6 hours, you get very different results, 0 hours banked in scenario 1 and 0 hours banked in scenario two, but the sloth index (excess sleep) is way higher in the second scenario.

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I love the term sloth index – HLGEM May 17 '12 at 18:06

Based solely on my own personal and unscientific experience, whenever I follow a regimen similar to Schedule 2, the 2nd day I'm always much more tired feeling than the first day. I seem to be fine with a reduced sleep schedule on the first day, however it adds up the more you do it consecutively.

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+1 as this is my own experience as well. – Joshua Drake May 17 '12 at 19:33

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