Sleeping Eight Hours or More Raises Mortality Risk for Older Adults in Spain 10 Hours of Sleep Each Night Linked to 73% Greater Risk of Death
In a study of nearly 4,000 people aged 60 and older, those who slept eight or more hours a night were at increased risk for dying than those who slept seven hours. What's more, the risk of death increased progressively with each extra hour of sleep.
New Research in the Journal of the American Geriatrics Society
The study explored the link between sleep duration and risk of death. The researchers followed 3,820 people over the age of 60 living in the community in Spain. The researchers were from the Department of Preventive Medicine and Public Health at the School of Medicine, Universidad Autónoma de Madrid / IdiPAZ and from the CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain.
The researchers took sex, age, lifestyle variables, and chronic diseases, including high blood pressure (hypertension), sleep quality, and anti-anxiety medication use into consideration. This allowed them to determine whether or not the link between sleep duration and mortality was connected to health issues, rather than to sleep time.
During the study, 897 deaths occurred. The researchers discovered that mortality was higher in people who slept less than five hours a night and for those who slept more than seven hours a night. What's more, the risk of death increased progressively with the amount of time people slept. Those who slept eight, nine, 10, or more than 11 hours a night had a 34%, 48%, 73%, and 66% greater risk of death than those who slept seven hours. People who slept less than five hours a night had a 42% greater risk of death than those who slept seven hours.
People who slept six hours a night had an increased risk of death only when cognitive function was mildly affected. There was no increased risk of death for healthy people who slept six hours a night versus seven hours a night.
However, the researchers discovered that even people in good health were adversely affected by sleeping more than seven hours a night. Though reasons for the connection are still unclear, the researchers pinpointed two factors for consideration. "The association between longer sleep and mortality could be due in part to a higher frequency of sleep complaints, such as frequent waking, apnea, or insomnia among people who sleep longer," said Fernando Rodríguez-Artalejo, MD, PhD, professor of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid. "In fact, there is some evidence that poor sleep quality is linked to poorer health." As a result, poor sleep quality could be more important than sleep duration when it comes to raising mortality risk.
Another factor could be exposure to daylight, Dr. Rodríguez-Artalejo noted. "Long sleep duration is a marker of lower natural daylight exposure, which could increase mortality risk through biological and psychological mechanisms," he added.
What Should I Do?
"Sleeping too long could be a sign of an underlying health problem that needs to be investigated," says Dr. Rodríguez-Artalejo. If you have trouble sleeping, wake frequently during the night, wake and have trouble falling back to sleep, or if you regularly sleep more than eight or nine hours a night, talk to your doctor. Also let your doctor know if you sleep fewer than five hours a night.
This summary is from the full report titled, "Sleep Duration and Mortality According to Health Status in Older Adults." It is in the October 2010 issue of the Journal of the American Geriatrics Society. The report is authored by Arthur Eumann Mesas, MPH; Esther López-GarcÃa, PhD; Luz Ma León-Muñoz, PhD; Pilar Guallar-Castillón, MD, PhD; Fernando Rodríguez-Artalejo, MD, PhD.