The researchers found that each additional nap per day was associated with a 7 percent higher risk of death, each additional hour of daytime napping raised that risk by 13 percent, and people who tended to nap in the morning had a 30 percent higher mortality risk than afternoon nappers.
That doesn’t mean naps are dangerous. Research shows naps can boost memory, focus, and creativity, and they’re culturally accepted in many countries, including Spain, Italy, China, and Japan. The problem is when napping becomes excessive or starts creeping into the morning, said the study’s lead author, Chenlu Gao, a researcher in the Department of Anesthesiology at Mass General Brigham.
Frequent morning naps may signal underlying problems such as sleep apnea, depression, chronic pain, heart disease, neurodegeneration, or circadian rhythm disruptions, she said. It also may signal a heightened risk of Alzheimer’s disease, with morning and irregular naps linked to worsening brain health.
“It is important to note that this is correlation, not causation,” said Gao. “Now that we know there is a strong correlation between napping patterns and mortality rates, we can make the case to implement wearable daytime nap assessments to predict health conditions and prevent further decline.”
The relationship between napping and health is understudied, especially in younger adults, said Gao, who is also a research fellow in MGB’s Division of Sleep and Circadian Disorders.
Gao couldn’t draw any conclusions for younger populations from her study, she said. For younger adults in the US, workplace napping is often stigmatized or prohibited. Still, some professionals are embracing short “microsleeps” to stay productive, especially in workplaces where workers can feel “digital overload.”
“For people who have trouble staying awake, it’s important to find out why. It could be sleep apnea or sleep deprivation,” she said.
Dr. Tony Cunningham, director of the Center for Sleep and Cognition at Beth Israel Deaconess Medical Center and professor at Harvard Medical School, commended the study for investigating links to mortality but cautioned against acting too quickly on the findings.
“There’s nothing inherently bad about napping,” he said. “Sure, it can get out of control, but habitual napping can be a good thing, especially if it’s part of your normal sleep routine.”
He said sleep habits change throughout a person’s life. It’s likely that younger adults aren’t getting enough sleep at night due to work, stress, hormonal imbalances, or, like him, having young kids disrupting their sleep.
“Once we reach 80+, sleep becomes more fragmented. If there’s a sudden shift, like you’re sleeping, napping, and still not feeling rested, that could be an alarm bell,” he said. “The duration and placement of naps are important. If it’s a sporadic four-hour afternoon nap, you’re starting a negative cycle feedback loop.”
He recommends naps for 30 minutes or less. “Even a nap as little as six minutes can make a difference.”
“If you’re someone who is going through menopause, it absolutely makes sense you need to recharge the battery, but you need to make sure it doesn’t impact your next night of sleep,” he said. “You can sleep seven hours and still feel like you need a nap. Traditionally, habitual nappers see tremendous benefit.”
For the study, Gao and researchers with the Rush Memory and Aging Project looked at the cohorts’ initial nap assessments from 2005 and compared those to their more recent habits in 2025. For those who died since their initial assessment, they looked at how napping may have predicted their mortality risk.
She and her colleagues adjusted for a range of factors, such as sleep medications, chronic conditions, physical activity, race, ethnicity, and depression. They also tracked the frequency, duration, and variability of the days when people took naps and the reasons why.
“We were most surprised to see morning nappers had a greater mortality risk,” Gao said. “Napping could signal a change in health conditions if people have trouble staying awake, especially in the morning hours. We should be alert after a good night’s sleep.”
So what counts as a ‘good’ nap?
Sleep specialists generally recommend keeping naps short and taking them in the early afternoon, ideally before 3 p.m. Longer naps can leave people groggy and interfere with nighttime sleep.
“Napping can help return immune markers to baseline after a night of poor sleep, effectively ‘repairing’ some damage from sleep deprivation,” said Dr. Aarti Grover, director of the Center for Sleep Medicine at Tufts Medical Center.
“A 10– to 20-minute power nap significantly boosts alertness, memory consolidation, and learning capacity. Occasional naps a few times a week are OK if needed and can help reduce stress by improving emotional regulation, making you less impulsive and irritable,” Grover said.
The study found that naps longer than an hour were more consistently associated with health risks, whereas shorter naps were more likely to be restorative.
“I think the reason for their nap is really important,” Gao said. “Our participants don’t have a culture of napping, but other cultures do. We do need more studies to determine whether napping is beneficial.”
Gao suggested going to bed and getting up at the same time every day, avoiding caffeine and alcohol (especially late in the day), avoiding using electronics before bedtime, and getting more sunlight in the morning.
She cautioned against using commercially available sleep trackers because their accuracy varies.
The key questions to ask yourself, Gao said, are:
Are you napping because you can’t stay awake during the day?
Has your need for naps changed suddenly?
Are you having trouble sleeping at night?
If the answers to any of these questions are yes — especially if you are older and suddenly taking longer, more frequent, or morning naps — it may be worth checking with your doctor, Gao said.
Sarah Rahal can be reached at sarah.rahal@globe.com. Follow her on X @SarahRahal_ or Instagram @sarah.rahal.