Long Sleep Associated Again With Greater Mortality Than Short Sleep
Two 2017 and 2018 meta-analyses found that both short and long sleep were significantly related to increased mortality and morbidity. However, using 65 years of age as a cut off, both studies found increased mortality among individuals with long sleep, but no significant association between short sleep and mortality.
In a new study on sleep duration and mortality, 38,000 subjects below age 65 were followed for 13 years for all-cause mortality after baseline assessment of their weekday and weekend sleep. The results showed that sleeping 5 hours or less, or 9 or more hours, on weekdays and weekends was associated with a higher mortality rate compared with those consistently sleeping 6 or 7 hours per night on weekdays and weekends. However, short weekday sleepers who compensated by sleeping more than 5 hours on weekends did not show elevated mortality risk. These results imply that short weekday sleep is not a risk factor for mortality if it is combined with longer weekend sleep.
In summary, these findings indicate that mortality risk is increased when both weekday and weekend sleep is short or long in subjects below the age of 65 years. However, when weekend sleep is extended after short weekday sleep, no association with mortality was seen.