Sleep Debt
The concept of "Sleep Debt" was brought into the limelight largely by Dr. William C. Dement in his work "The Promise of Sleep." What it basically says is, you have a base number of hours you need to sleep each night, and variations to that number will add or subtract from the bank.

Also, it's good to have an underlying "debt" of maybe 10-20 hours so that you are able to attain sleep properly. This is in regards to the overall debt, not "this week's" debt, or "yesterday's" debt.

Doing a little C&P from a post I did elsewhere:

(1) There are a number of components that go into making you "feel better" as you treat OSA. Paying off the sleep debt is only one component of that.
(2) This also assumes that your sleep quality is normal. If you're still having a pile of arousals and/or poor architecture, that's going to be a problem.
(3) If you're not sleeping more than your base sleep requirement, the answer as to when you pay off your sleep debt is "never".
(4) It also depends on how big your debt is.

As noted in the Dement work, there are a number of ways to determine your basic sleep needs, and then you can do a running total of your sleep debt. But to skip ahead, there are several methods to estimate your sleep debt at the moment of your transition from treatment to now. The easiest of these is to use the Epworth Sleepiness Scale. This method gives you a number that quantifies your level of sleepiness and estimates your sleep debt. You probably did this prior to your sleep studies, if you don't remember the number, call the Sleep Laboratory and I'm sure they can find it for you. It looks like this:

Use the following scale to choose the most appropriate number for each situation:

0 = would never doze or sleep.
1 = slight chance of dozing or sleeping
2 = moderate chance of dozing or sleeping
3 = high chance of dozing or sleeping

Situation Chance of Dozing or Sleeping
Sitting and reading
Watching TV
Sitting inactive in a public place
Being a passenger in a motor vehicle for an hour or more
Lying down in the afternoon
Sitting and talking to someone
Sitting quietly after lunch (no alcohol)
Stopped for a few minutes in traffic while driving

Total score (add the scores up)

Dr. Dement equates the Epworth Score thus:
0-5 Slight or no sleep debt
6-10 Moderate sleep debt
11-20 Heavy sleep debt
21-25 Extreme sleep debt

The time needed to pay off the sleep debt depends on the size of the bill, whether it will be days or weeks (actually the sleep debt concept only goes out about two weeks, that's the extent of documented study. It probably levels out at some point for a number of reasons).

Anyway, get your score pre-test, that'll give you the size of the bill, then rate your Epworth Score now, and that should give you a rough idea on how many payments you have left.

Personally, I'm not sure if I completely buy into the concept entirely. Being a HCW for ** years, I know/have seen hundreds of people doing shift work whose debt must be thousands of hours. And I don't think they have to pay back the debt completely to be "normal" again. There must be a ceiling where you are "bankrupt", and are simply falling asleep at every opportunity, or an ESS of 24.

If people with huge sleep debts are simply allowed to "freewheel", sleep at much as they want over a period of days, they seem to correct (stabilize their total sleep time) after a period of time (and this is more in the neighborhood of days). Further, since the "rebound" phenomena disappears quite quickly, that certainly suggests that the correction is not linear. So if after 2 weeks you're still feeling no better, go back and look at those other points.

Cause don't forget, we're only talking about sleepiness here. Sleep deprivation has plenty of other harmful sequelae, like disruption of carbohydrate metabolism and endocrine function. And if you've had severe OSA with terrific desats for 10 years and/or have additional health issues, then who the heck knows. The sleep debt studies were conducted on "normal" people.

So think of this more as a "forest/trees" thing. If you're still only sleeping 6 hours a night, not paying attention to all the other health issues (eating habits, weight and exercise) and/or haven't normalized sleep architecture (still have sleep disruption or insomnia from some other thing), then the debt will remain.

If all these things are taken care of, and you "free-wheel" at least a little bit, I'll go out on a limb and say you'll be pretty well paid off after 2 weeks.

Reference: "THE PROMISE OF SLEEP", William C. Dement and Christopher Vaughan, Delacorte Press, 1999 (Great book, a bargain at 16 bucks)

Courtesy Sleepydave from the ASAA Apnea Support Forum.