Naps may be an easily trackable warning sign of underlying conditions or declining health among older adults, a new study suggests. Researchers followed 1,338 older adults for up to 19 years to track napping habits and associated mortality rates. The mean age of participants was 81 and 76% were women.

Participants wore an actigraphy device for about 10 days, and the team extracted sleep patterns and mapped nap length, frequency, time of day, and day-to-day variability.

More frequent naps and morning naps were associated with higher mortality. Each additional hour of daytime napping per day was associated with around a 13% higher mortality risk; each extra nap per day was associated with around a 7% higher mortality risk; and morning nappers had a 30% higher mortality risk compared to afternoon nappers. Irregular napping patterns were not associated with any increased mortality risk.

“It is important to note that this is correlation, not causation," said lead author Chenlu Gao, PhD, Mass General Brigham, Harvard Medical School, Boston, Massachusetts. "Excessive napping is likely indicating underlying disease, chronic conditions, sleep disturbances, or circadian dysregulation. 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.”

To read the full study, published in JAMA Network Open, click here