Daytime sleep: A long-running study of older adults has found that certain daytime napping habits may be linked to a higher risk of death, adding to evidence that changes in sleep patterns later in life could signal underlying health problems.
The research, published in JAMA Network Open, followed 1,338 older adults for up to 19 years and found that people who took longer naps, napped more often, or tended to nap in the morning had higher mortality rates than others in the study.
The work was led by researchers from Mass General Brigham and Rush University Medical Center, who said the findings suggest daytime napping could serve as a simple and measurable marker of declining health in older adults.
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Lead author Chenlu Gao, PhD, from the Department of Anesthesiology at Mass General Brigham and an affiliated research fellow in sleep and circadian disorders, said earlier studies had already linked excessive napping in later life to conditions such as neurodegeneration, cardiovascular disease and greater illness burden. But many of those studies relied on people reporting their own habits, rather than using objective measurements.
According to Gao, this study is among the first to connect objectively measured nap patterns with mortality risk, while also looking at details such as how often people napped, how long they slept during the day, and whether those naps happened in the morning or afternoon.
Daytime napping is common among older adults, with previous estimates suggesting that between 20% and 60% nap regularly. While an occasional nap can be refreshing, heavier daytime sleep has increasingly been associated with poorer health.
To investigate further, the researchers used data from the Rush Memory and Aging Project, an ongoing cohort study launched in 1997 that focuses largely on cognition and neurodegeneration in older adults, most of whom were white and living in northern Illinois.
From 2005 onward, participants wore wrist activity monitors for 10 days so researchers could track rest and activity patterns. Using those data, the team examined nap duration, how often naps occurred, the time of day they happened, and how much those habits varied from one day to the next.
By 2025, the researchers had gathered 19 years of data from 1,338 participants. When they compared initial napping patterns with deaths from any cause over the follow-up period, they found a clear pattern: longer naps, more frequent naps and morning naps were all linked to higher mortality.
The study found that each additional hour of daytime sleep was associated with about a 13% higher risk of death. Each extra nap per day was linked to roughly a 7% increase in mortality risk. People who usually napped in the morning had a 30% higher mortality risk than those who tended to nap in the afternoon.
Not every nap-related pattern was tied to worse outcomes. Researchers found that irregular day-to-day napping did not appear to raise mortality risk.
Gao said the findings should not be read as proof that napping itself is harmful. Rather, she said, excessive daytime sleep is more likely to reflect underlying disease, chronic illness, sleep problems or disruption of the body’s internal clock.
The researchers say the results strengthen the case for using wearable devices to monitor napping habits in older adults, with the goal of identifying possible health issues earlier and helping prevent further decline.