The Surprising Link Between Daytime Naps And Cognitive Decline

Taking a nap in the early afternoon is often considered healthy, especially if you're making up for lack of sleep. According to the American Heart Association, a short nap of about 20 minutes around 3 p.m. can be a mood booster, and it could increase alertness and improve memory. In addition, a nap might even make you more creative.

That said, there is a downside to naps. For starters, napping any later than 3 p.m. might interfere with nighttime sleep. Naps that last longer than 20 minutes can be problematic, too. They can make it more difficult to fall asleep at night and are linked to depression, heart disease, and diabetes (per Harvard Health Publishing). Longer naps can also indicate you lack sound, restful sleep or have a sleep disorder. Now, recent research shows that older individuals who take regular naps might be at a greater risk of developing dementia.

Longer naps are linked to Alzheimer's Disease

The 2022 study, which lasted 14 years, was published in Alzheimer's and Dementia: The Journal of the Alzheimer's Association. It examined the sleep habits of 1,401 participants between 74 and 88 years of age. Data showed that those who napped for more than one hour a day had a 40% increased likelihood of developing Alzheimer's disease than those who did not take long naps or any naps (via CNN). The research also showed that adults with no cognitive decline saw an increase of nap time by 11 minutes per day. Naptime jumped by 24 minutes in those with mild cognitive impairment and 68 minutes in those diagnosed with Alzheimer's.  

Dr. Richard Isaacson, director of the Alzheimer's Prevention Clinic in the Center for Brain Health at Florida Atlantic University's Schmidt College of Medicine, told CNN that Alzheimer's causes changes in sleep behavior. "Excessive napping may be one of the many clues that a person could be on the road to cognitive decline, and trigger an in-person evaluation with a treating physician," he said. 

Dr. Yue Leng, assistant professor of psychiatry at the University of California San Francisco, added that there wasn't enough evidence to support the theory that long naps caused cognitive decline, but they could be an indicator of it, according to CNN. Leng suggested that older people should limit nap times to 20 minutes before 3 p.m. and discuss any changes in nap behaviors with their doctor.