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What Is Sleep Debt, and Can I Pay it Off?
By now (if you’ve spent any time on this site) you may have heard that for optimum health and wellbeing, your Average Joe (and Josephine) needs seven to nine hours of sleep per night. And from personal experience you know that you, and many others, often fall short of this goal.
Every time you or Average Joe don’t hit that target number, you’re going into what’s called “sleep debt,” a colloquialism used to describe the phenomenon of accumulated fatigue (physical or mental) when you (or Joe) fail to log a sufficient amount of rest.
All those hours of lost slumber end up in a health debit column. Unfortunately, we don’t get an email notification that we’re in arrears. In fact, according to Harvard’s Family Health Guide, the greater the sleep debt, the less capable we are of recognizing it. Studies indicate that a person’s cognitive skills pretty much tank when he or she experiences prolonged periods of shortened sleep — four to six hours per night. Finding yourself “in debt” too often also increases the risks and consequences over time.
What do the non-believers think?
Researchers who question the phenomenon say that the amount of time a person should sleep — called the “adaptive sleep window” — can vary by as much as three hours per person, so anywhere between six and nine hours might work. And while they acknowledge that increased sleep is of course one way to decrease fatigue or daytime sleepiness, another way is to make one’s waking hours “more challenging and eventful.”
The example often given to support this view is that of animals, who sleep more and longer in captivity than they do in the wild. Is a bear in a zoo finally catching up on the rest it needs, or is it sleeping more because it’s bored out of its skull?
And from the camp that acknowledges sleep debt?
A couple of years ago, researchers tackled the conundrum by rounding up a group of participants and measuring the known markers of being either well-rested, or sleep deprived (attention, stress, daytime sleepiness and low grade inflammation). After a baseline for these markers was established, participants’ sleep was limited for six nights; then they were allowed three nights of 10-hours catch-up sleep and evaluated.
Findings indicated that following the catch-up sleep, daytime drowsiness and inflammation (as measured via a biomarker from blood samples) returned to baseline levels. Cortisol levels (which measure stress) remained unchanged. Score two and a half for sleep debt theory.
However — attention levels dropped significantly after participants were sleep deprived and did not return to baseline levels after the catch-up period. This was concerning, since attention directly impacts a person’s performance.
The researchers’ takeaway: Catch up sleep can help pay off some sleep debt, but definitely not all of it.
So the jury’s still kind of out.
When it comes to sleep theory, all the scientific debate is, honestly, rather academic. It all boils down to this: Are you tired? Do you feel like crap? Are you having trouble focusing, and enjoying your life?
If so, there are a number of approaches you can try to solve the problem.
Dr. Lawrence Epstein, author of The Harvard Medical School’s Guide to a Good Night’s Sleep, suggests that if you miss out on sleep during the week, you should indeed try to make it up on the weekend. So for instance, if you were down 10 or more hours because you were slammed at work and up late (meaning you logged maybe six hours a night rather than your hard eight), try to add an extra three to four hours of shuteye when the weekend comes.
If you’ve been running on fumes for a while, Epstein proposes a solution to long-term (cumulative) sleep debt that just about everybody can get behind: Take a vacation. Allow yourself to go to bed and wake at whatever time your body wants — no alarm clocks allowed.
Once you’re back on track, try to maintain a consistent schedule, going to bed and getting up at the same time each day.
The contrarian researcher who questions sleep debt, Professor Jim Horne, notes that a 20-minute nap may be equally as effective in reducing daytime drowsiness as adding an hour of sleep to your night. So if you were up last night, see if you can grab a quick snooze during the day.