We’ve all heard the old adage, “I’ll sleep when I’m dead.” Yes, Americans tend to work hard and play hard — and think that sleep isn’t all that important. If you rely on one long night of sleep to recover from a whole week’s worth of deprivation, it seems that’s not really enough. According to a new study in the journal Sleep, one night of 10 hours of sleep does not restore us to full cognitive functioning after a week of insufficient sleep.
Sleep deprivation causes behavioral abnormalities and impairs your thought process, becoming worse the longer you are sleep-deprived. Even if you sleep a few hours per night, you will likely experience the slow accumulation of the negative effects of sleep-deprivation over a period of several days. The authors of the study wanted to determine how easily people recover from a model of sleep restriction that reflects the average American’s schedule: a five-day work-week with relatively little sleep, followed by an extended “recovery” sleep on at least one weekend night.
The researchers enrolled 159 healthy adults between the ages of 22 and 45. The subjects agreed to spend 12 days in a controlled sleep laboratory where the researchers could monitor their vital signs, cognitive abilities and behavioral tendencies while controlling the amount of sleep they got. All subjects were allowed to sleep for 10 hours per night for the first two nights. During this time, the researchers established baseline data for all cognitive and behavioral tests, as well as for brain activity during sleep. For the next five nights, the members of the experimental group were only allowed to sleep for four hours per night, while the members of the control group continued to sleep 10 hours per night. On the final night, subgroups within the experimental group received different “doses” of recovery sleep, anywhere between zero and 10 hours.
As the week progressed, the members of the experimental group reported feeling significantly more tired, and showed the expected decreases in their abilities to think quickly and stay awake. Even after up to 10 hours of sleep on the recovery night, sleep-restricted subjects not only failed to match the test performances of people in the other control group, but they also could no longer achieve their baseline levels of cognitive performance or behavioral wakefulness.
The researchers concluded that to fully function again after a period of sleep-deprivation or restriction, you may need to sleep for up to 14 hours in one session. However, they’re not sure that full recovery is possible from one sleep session, no matter how long. If that’s the case, multiple nights of longer sleep may be necessary to become 100 percent again.
Remember that your ability to function at work may suffer if you frequently decide to catch up on those “Mad Men” episodes instead of going to sleep early. However, if you find yourself sleep-deprived after a busy week, be sure to allow yourself to sleep as long as you can both weekend nights in order to recover as much as possible.