Slept Debt Doesn't Work With DSPS

See the paper "Poor Compensatory Function for Sleep Loss as a Pathogenic Factor in Patients with Delayed Sleep Phase Syndrome" Uchiyama, et al. (2000) Sleep. Vol 23, No. 4

Kevin's Thoughts

Thank you very much for the reference. For those visitors wanting to see the paper mentioned you can find it in the archives of the Journal Sleep, right here. To see the whole paper simply click "View Full Text" in the gray box to the right.


Unfortunately, it's not as easy as saying simply that sleep debt does not work to help a delayed sleep phase. In fact, it can work quite well if used properly as a strategy in many mild cases, particularly in adolescents. To see why this is, one has to understand how our homeostatic sleep drive operates.

Our homeostatic sleep drive is the internal process that governs our bodies' drive to sleep at any given time during the day. That drive is counterbalanced by two factors: clock-dependent alerting, the mechanism controlled by our biological clock that releases chemicals that make us tired or alert, and sleep debt. In a nutshell, these factors compete against each other to determine whether we feel sleepy or wide awake. If our sleep debt is low and our clock-dependent alerting is high we will be awake with a very low tendency to fall asleep. But as our sleep debt increases it will take less and less clock-dependent alerting to make us sleepy.

As the name implies the sleep drive functions to maintain a homeostatic state when it comes to the amount of sleep we obtain. If we need more sleep (i.e. we have a large sleep debt) the drive to sleep increases against clock-dependent alerting so that hopefully our body obtains that sleep so it can function at a higher level.

In a traditional sleep schedule an individual would have a high sleep drive at night and a low sleep drive during most of the day. In a delayed sleep phase schedule, an individual's clock-dependent alerting is stronger late at night, making it difficult to fall asleep while that alerting is still strong. To combat that high clock-dependent alerting, a higher sleep debt can be used so that as soon as the scale tips to favor sleep, and before the clock-dependent alerting gets too high late in the night, the individual is able to fall asleep.

Of course, this method does not work for every case, particularly in chronic cases of delayed sleep phase syndrome where sleep debt is already astronomically high. If it's already huge then other treatment options must be sought out. But for transient delayed sleep phases, particularly in adolescents, college students, or individuals with low sleep debts obtained by sleeping in, the technique can be highly effective. It takes diligence and conscious effort, but it can be done.


As this argument about semantics indicates, saying that sleep debt can work in some cases of DSPS is not in disagreement with the article, but rather just recognizes that there are some people with persistent and unwanted delayed sleep phases who don't necessarily have an inability to compensate for lack of sleep.

Do you follow? Feel free to object or add more of an argument to any point of view using the "Post Comments" link below.