Does Taking Longer Naps Increase Stroke Risk?

Napping for long duration during the day could be associated with an increased risk for stroke, according to new research.

The paper authors, publishing in Neurology, sought to evaluate any links between sleep duration, midday napping, sleep quality, and change in sleep duration with risk for incident stroke.

“More research is needed to understand how taking long naps and sleeping longer hours at night may be tied to an increased risk of stroke, but previous studies have shown that long nappers and sleepers have unfavorable changes in their cholesterol levels and increased waist circumferences, both of which are risk factors for stroke,” author Xiaomin Zhang, MD, PhD, of Huazhong University of Science and Technology in Wuhan, China, explained in a press release. “In addition, long napping and sleeping may suggest an overall inactive lifestyle, which is also related to increased risk of stroke.”

The study included 31,750 individuals in China (average age, 62) with no history of stroke or other health problems at baseline. The researchers used Cox regression models to estimate hazard ratios for incident stroke (all confidence intervals, 95%). Average follow-up was six years.

According to the results, individuals reporting longer sleep duration (nine hours per night or more) had a greater risk of total stroke (HR=1.23; 95% CI, 1.07 to 1.41). Shorter sleep duration (less than six hours per night) had no significant effect on stroke risk. When one napped for more than 90 minutes compared to a shorter duration (between one and 30 minutes) was 1.25 (95% CI, 1.03 to 1.53). The findings were reported as similar for ischemic stroke. Participants with poor sleep quality (vs. good sleep quality) had increased risk for total (by 29%), ischemic (by 28%), and hemorrhagic stroke (by 56%). The authors reported joint effects when nine hours or more of sleep per night was combined with more than 90 minutes of napping (HR=1.85; 95% CI, 1.28 to 2.66), and sleeping more than nine hours per night plus poor sleep quality (HR=1.82; 95% CI, 1.33 to 2.48). Individuals who slept more than nine hours per night, or who switched from seven to nine or more hours per night had a nigher total risk.