Regular daytime napping may be linked to an increased risk of dementia among older adults, according to a new medical study.
An afternoon nap can help restore energy during the day, but researchers say frequent or prolonged daytime sleep may also be a sign of underlying health problems.
A study by the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health analyzed health data from nearly 9,000 people aged 65 and older.
The participants were followed for 10 years. Researchers found that older adults who napped daily or frequently had up to a 48% higher risk of dementia.
The study also found that unplanned daytime napping or sleeping for around 30 minutes in the afternoon was associated with up to a 40% higher risk of dementia.
Researchers believe there may be a relationship between frequent napping and dementia. They suggested that frequent daytime sleep could be associated with changes in areas of the brain involved in regulating wakefulness.
However, researchers stressed that the findings should not be considered conclusive. The study does not establish that napping itself causes dementia.
They said frequent napping could instead be an indicator of underlying changes in the brain, particularly among older adults, and that further research is needed to better understand the relationship.
The findings were published in the Journal of Gerontology.
Earlier Research Also Linked Excessive Daytime Sleepiness to Health Risks
A separate study conducted in April 2026 by researchers at Brigham and Women’s Hospital and Rush University Medical Center examined 1,338 older adults over a period of 19 years.
That research found that frequent daytime sleepiness in older adults may not simply result from insufficient sleep but could also indicate underlying health conditions.
Researchers tracked participants’ daytime sleeping habits and mortality rates and found an association between frequent, prolonged naps and a higher risk of death.
According to the study, excessive daytime sleepiness in middle age and later life may be associated with cognitive decline, cardiovascular disease and other health problems.
Researchers also reported that between 20% and 60% of older adults take daytime naps.
The findings suggest that occasional napping may have benefits, while a sudden or persistent increase in daytime sleepiness or napping may warrant attention, particularly among older adults.