A large-scale study analyzing the link between recovery sleep and mortality found that getting about one hour of additional sleep after a sleep-deprived day significantly reduces the risk of premature death, a Tsinghua University research team in China reported in the journal Nature Communications on Thursday.
The team analyzed more than 574,000 days of sleep data from approximately 85,000 participants in the UK Biobank. Participants wore wrist-worn sleep tracking devices, and their average daily sleep was 6.43 hours. About 30 percent of the participants experienced "sleep restriction," sleeping less than their personal average or the average for their age group. Of these, nearly half showed a "recovery sleep" pattern, sleeping about one hour more on the day after sleep restriction. Notably, most of the recovery sleep occurred on weekdays rather than weekends.
Participants who did not take recovery sleep after sleep restriction had a 15 percent higher probability of all-cause mortality over the following eight years compared with the group that experienced no sleep restriction. The gap was even more pronounced among those with chronic sleep deprivation, who slept an average of only 5.7 hours excluding sleep-restriction periods and the days surrounding them. By contrast, the mortality risk of the group that took additional sleep the day after sleep deprivation showed no statistically significant difference from those who routinely got sufficient sleep. The same pattern was confirmed when sleep deprivation continued for one or two consecutive days, and verification using data from the U.S. National Health and Nutrition Examination Survey (NHANES) yielded similar results.
There are limits to interpreting the study, however. Jean-Philippe Chaput, a sleep expert at the University of Ottawa in Canada, said the findings are "consistent with the biological mechanism that recovery sleep can partially compensate for acute sleep deprivation," but added that the observational nature of the study makes it impossible to prove that sleep deprivation directly causes death or that recovery sleep prevents it. "The fact that recovery sleep is possible should not be interpreted as meaning that repeatedly cutting sleep during weekdays is harmless," he stressed.
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