Seven Hours of Sleep Is Ideal for Most Adults, Study Finds

Seven hours of sleep—no more and no less—may be the optimal amount of rest for most adults, new research shows.

The new study, published in Nature Aging, shows that among people ages 38 to 73, getting seven hours of sleep each night provides the most benefit for cognitive and mental health. It's best for those sleeping patterns to remain consistent, too—meaning getting seven hours of sleep once in a while won't cut it for brain health.

"Getting a good night's sleep is important for all stages of life, but particularly as we age," study co-author Barbara Sahakian, FMedSci, DSc, a professor in the department of psychiatry at the University of Cambridge, said in a press release. "Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and wellbeing and avoiding cognitive decline, particularly for patients with psychiatric disorders and dementias."

Though the study provides a more accurate number of hours for optimal sleep health, there are limitations to the research, which included primarily white participants (94%). The lack of diversity makes the results difficult to apply to heterogeneous populations.

"Race and ethnicity should be explored in similar studies to determine their contribution to sleep time requirements, sleep-related genetics, and cognitive consequences of short and long sleep times," Margarita Oks, MD, a critical care pulmonologist and sleep expert at Lenox Hill Hospital who was not involved with the new study, told Health. "Additionally, the database used in the study had relatively healthy participants, and it would be interesting to know if significant medical comorbidities would impact the ideal sleep time, even in this primarily white cohort."