Older man napping

Excessive napping may signal failing cognitive health in older men, according to a new study by University of California, San Francisco researchers.

Wrist-mounted sensors were used to track the sleep habits in nearly 3,000 men aged 65 and older for five days, and the investigators then measured cognitive function at regular intervals over 12 years. Cognitive impairment was determined by physician diagnosis, the use of Alzheimer’s medication and other signs of significant decline.

Men whose daily naps averaged two hours or more at the beginning of the study were 66% more likely to have clinically significant cognitive impairment than those who napped for 30 minutes or less. And the results suggest that nighttime sleep disruption is not likely to contribute to the problem: participants who slept well at night but napped excessively were more likely to experience decline than those who did not sleep well at night, the research team wrote.

“The results suggest that clinicians should pay close attention to 24-hour sleep patterns in older adults,” senior author Kristine Yaffe, M.D., said in a statement.

In a previous study, the researchers found that men who napped for more than an hour a day were two-to-three times more likely to develop Parkinson’s disease within 11 years.