Adequate sleep is essential not only for mental health, but also for immune function, cognitive function, and physical health. However, sleep duration varies with age, with infants sleeping more than 12 hours per day but decreasing with age.
A famous study examining the relationship between sleep duration and mortality, published in the Annals of Psychiatry, has recently received renewed attention due to the increase in sleep disorders.
This study involved 1.1 million Americans, with an average age of 57, who participated in the National Cancer Prevention Study. They were monitored for their daily sleep duration and followed for an average of six years to determine overall mortality rates.
The study found that the average sleep time among the subjects was eight hours per night, and that 9.4% of men and 5.1% of women died during the follow-up period. Overall, those who slept seven hours per night had the lowest mortality rate. . A pattern of higher mortality rates was observed with sleep durations exceeding 7 hours. Those who slept more than 8.5 hours or less than 4 hours had a 15% higher mortality rate. Those who took sleeping pills daily had a 24% higher mortality rate.
