Short, long sleep duration associated with increased mortality

From: American Academy of Sleep Medicine

WESTCHESTER, Ill. – A study published in the December 1 issue of the journal SLEEP is the first to show that both a decrease and an increase in sleep duration are associated with an elevated risk of mortality by cardiovascular and non-cardiovascular means, respectively.

The study, authored by Jane E. Ferrie, PhD, of the University College London Medical School in London, U.K., focused on 10,308 participants between 35 and 55 years of age. Baseline screening (Phase 1), conducted between 1985 and 1988, involved a clinical examination and a self-administered questionnaire. Data collection at Phase 3 (1992-1993) also included a clinical examination (8,104 participants) and questionnaire (8,642 participants).

“In terms of prevention, our findings indicate that consistently sleeping seven or eight hours per night is optimal for health,” said Dr. Ferrie. “The indication that mortality rates are lower in participants who slept five to six hours or less at Phase 1 but who reported extended hours of sleep at Phase 3 implies that increasing sleep duration in short sleepers is likely to have health benefits. In contrast to this, the finding that an increased duration of sleep among those sleeping seven to eight hours is associated with higher levels of mortality implies that sleep restriction should at least be considered.”

These are very interesting and significant findings. If you're a short sleeper, you may be able to decrease your risk of mortality by sleeping more—up to eight hours a night. If you're already sleeping seven or eight hours a night, sleeping longer might increase your risk of mortality.

However, I get a bit uneasy whenever I hear people advocating sleep restriction. Let's keep in mind that these are statistical generalizations. And you're not a statistic, you're a person. So, if you feel you need a bit more than eight hours sleep to feel rested, alert, and energetic, I would encourage you to satisfy that need. (I personally find that about 8 hours and fifteen minutes is the ideal sleep duration for me, and I am certainly not going to cut back on that because of this finding!) And if from time to time you feel the need to sleep even longer for one or several nights, that's okay, too. Limited periods of sleep extension—up to 10.2 hours per night—have been shown to yield above-normal improvements in alertness, reaction time, and mood. They may have real therapeutic value.

Image: "The Dream" by Henri Matisse