Chenlu Gao, PhD, from Massachusetts General Hospital and Harvard Medical School

Chenlu Gao, PhD

Naps at Noon Linked to Mortality Risk in Older Adults, with Chenlu Gao, PhD

A study found that frequent, longer, and irregular daytime 

, especially around noon or in the early afternoon, are linked to a greater mortality risk in middle-to-older adults.

Chenlu Gao, PhD, from Massachusetts General Hospital and Harvard Medical School, presented this study at 

SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies

, from June 8 to 11 in Seattle. HCPLive sat down with Gao during the meeting to discuss the relationship between specific napping patterns, such as occasional or habitual napping, and a greater mortality risk in middle-to-older adults.

“We did not specifically examine each specific cause of death, and I think that's [a] great direction for future research in terms of the strength of the associations,” Gao said. “They were statistically significant, but relatively small in magnitude, meaning that napping patterns only explained a small proportion of mortality risk.”

Gao and colleagues sought to determine whether actigraphy-measured objective daytime napping behaviors predict all-cause mortality in middle-to-older aged adults in the US. Leveraging UK Biobank data, the study included 86,565 participants (57% females) with a mean baseline age of 63 years. Participants did not have a shiftwork history.

Participants completed 7-day actigraphy monitoring and had data linked to mortality registries. Investigators used the Cole-Kripke algorithm to identify daytime sleep episodes from actigraphy and tracked the following metrics: mean nap duration between 9 am – 7 pm, intra-individual variability across days in nap duration, and times of any 2-hour naps between the hours of 9 – 11 am, 11 am – 1 pm, 1 – 3 pm, 3 – 5 pm, and 5 – 7 pm.

The team assessed the associations between napping patterns and all-cause mortality through Cox proportional hazard models, adjusted for demographics, body mass index (BMI), smoking, alcohol consumption, comorbidities, nighttime sleep duration, and chronotype.

The study found mean nap duration was 0.40 hours/day (IQR, 0.19 – 0.77), and intra-individual variability of nap duration was 0.39 hours (IQR, 0.19 – 0.67). When it came to napping behaviors, 34% of participants took naps between 9 – 11 am, 10% between 11 am – 1 pm, 14% between 1 pm – 3 pm, 19% between 3 pm – 5 pm, and 22% between 5 pm – 7 pm.

During the 8-year follow-up, 3.4% of participants died, with an average survival time of 4.19 (range, 0.03 – 8.15) years after baseline. The analysis showed that longer nap duration (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.16 – 1.24;

 < .0001), greater intra-individual variability (HR, 1.14; 95% CI, 1.10 – 1.18; 

 < .0001), and more naps between 11 am – 1 pm (HR, 1.07; 95% CI, 1.03 – 1.11; 

 = .0005) and between.1 – 3 pm (HR, 1.07; 95% CI, 1.03 – 1.12; 

Gao noted that, despite these findings, the analysis did not provide direct evidence that 2-hour naps or early afternoon naps pose a mortality risk, since this study is merely observational and did not show causation. However, the study did demonstrate the association between certain napping behaviors and an increased mortality risk.

“We think it's more likely that napping patterns reflect underlying health conditions,” Gao said. “For example, excessive and irregular napping could be a result of poor nighttime sleep, sleep disorders, circadian disruption, or other health conditions, such as cardiovascular disease, metabolic disorders, mood disorders, or early neurodegeneration. I think if clinicians were to do any interventions, they should be targeting the causes of excessive napping rather than simply trying to eliminate napping itself.”

Chenlu Gao, Ruixue Cai, Xi Zheng, Lei Gao, Kun Hu, Peng Li, 0350 Objectively-Assessed Napping Behaviors Predict Mortality in Middle-to-Older Aged Adults, 

, Volume 48, Issue Supplement_1, May 2025, Page A152, 

https://doi.org/10.1093/sleep/zsaf090.0350

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A study presented at SLEEP 2025 found longer and more variable napping patterns are associated with increased all-cause mortality in middle-to-older aged adults.


Chenlu Gao, PhD

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