Most combinations of insufficient nighttime sleep and daytime napping increased CVD risk among middle-aged and older Chinese adults, with the combination of less than 6 hours nighttime sleep with short napping (≤0.5 h) associated with the highest observed CVD incidence.
Insufficient nighttime sleep (<6 hours) was independently associated with a higher risk of cardiovascular disease.
The combination of less than 6 hours of nighttime sleep with short napping (≤0.5 hours) was associated with the highest CVD risk observed among all sleep combinations.
Insufficient nighttime sleep (<6 hours) without any daytime napping was associated with significantly higher CVD risk.
Insufficient nighttime sleep combined with long napping (>1 hour) was associated with significantly higher CVD risk.
The combination of insufficient nighttime sleep with moderate napping duration was not associated with increased CVD risk.
Stratified analysis revealed significant heterogeneity by gender, with less pronounced associations between sleep combinations and CVD risk in men compared with women.
The study population consisted of middle-aged and older Chinese adults followed for approximately nine years using nationwide longitudinal data.
This research suggests that how people combine nighttime sleep and daytime napping has important implications for cardiovascular disease (CVD) risk in middle-aged and older adults. Using nearly a decade of data from nearly 8,000 Chinese adults, the study found that getting less than 6 hours of sleep per night was associated with roughly 19% higher risk of developing CVD compared to people who slept an adequate amount. Among those with short nighttime sleep, adding a very brief nap (30 minutes or less) was linked to the highest CVD risk — about 56% higher than people who slept adequate hours and didn't nap at all. Interestingly, the study found that people who slept less than 6 hours per night but took a moderate-length nap did not show a statistically significant increase in CVD risk, raising the possibility that moderate napping might partially offset some risks associated with insufficient nighttime sleep. In contrast, either not napping at all or napping for more than an hour when nighttime sleep was short were both associated with elevated CVD risk. The study also found that these associations were stronger in women than in men. This research suggests that the relationship between sleep and heart health is not simply about total sleep time, but also about how nighttime and daytime sleep are combined. These findings could help inform more nuanced public health advice about sleep habits, particularly for older adults, though the self-reported nature of sleep measurements and the observational study design mean that causal conclusions cannot be drawn directly from these results.
Xiong W, Li W, Xue J, Zhang L, Li J, Ma S, et al.. (2026). Impact of nighttime sleep duration and daytime nap combinations on cardiovascular disease risk in middle-aged and older Chinese adults: a nationwide prospective cohort study.. BMC public health. https://doi.org/10.1186/s12889-026-26516-z