Sleeping Longer Than 9 Hours Or Long Naps During The Day Increases Risk Of Strokes
Individuals who take long naps during the day or sleep nine or more hours
at night may have an increased risk of stroke
, according to a study published in Neurology
, the medical journal of the American Academy of Neurology.
Also, individuals who took a regular midday nap lasting more than 90 minutes
were 25 percent more likely to later have a stroke
than people who took a regular nap
lasting from one to 30 minutes. People who took no naps
or took naps
lasting from 31 minutes to one hour were no more likely to have a stroke
than people who took naps
lasting from one to 30 minutes.
Dr Xiaomin Zhang, MD, Ph.D., of Huazhong University of Science and Technology in Wuhan, Chin and study author told Thailand Medical
News, "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
. In addition, long napping
may suggest an overall inactive lifestyle, which is also related to increased risk of stroke
The research involved 31,750 people in China with an average age of 62. The people did not have any history of stroke
or other major health problems at the start of the study. They were followed for an average of six years. During that time, there were 1,557 stroke
All research participants were asked questions about their sleep
habits. Midday napping is common in China, Zhang said. Eight percent of the people took naps
lasting more than 90 minutes. And 24 percent said they slept nine or more hours per night.
The research found that people who sleep
nine or more hours per night are 23 percent more likely to later have a stroke
than people who sleep
seven to less than eight hours per night. People who sleep
less than seven hours per night or between eight and less than nine hours per night were no more likely to have a stroke
than those who slept from seven to less than eight hours per night.
The study findings were all adjusted for other factors that could affect the risk of stroke
. These include high blood pressure, diabetes and smoking.
Individuals who were both long nappers
and long sleepers
were 85 percent more likely to later have a stroke
than people who were moderate sleepers
The medical r
esearchers also asked people about how well they slept. People who said their sleep
quality was poor were 29 percent more likely to later have a stroke
than people who said their sleep
quality was good.
About 1 percent of cases per person-years of the long nappers
later had a stroke
, compared to 0.7 percent of cases per person-years of the moderate nappers
. The numbers were the same for the long and moderate sleepers, with 1 percent of cases per person-years compared to 0.7 percent of cases per person-years having a stroke
Dr Zhang added, "These results highlight the importance of moderate napping
duration and maintaining good sleep
quality, especially in middle-age and older adults.”
Dr Zhang noted that the study does not prove cause and effect between long napping
. It only shows an association. Limitations of the study include that information on sleep
was taken from questionnaires, not from recording people's actual sleep
and information was not collected on sleep
disorders such as snoring and sleep
apnea. Also, the study involved older, healthy Chinese adults, so the results may not apply to other groups.
Source Reference: Zhou L, et al "Sleep duration, midday napping, and sleep quality and incident stroke: The Dongfeng-Tongji cohort" Neurology 2019; DOI:10.1212/WNL.0000000000008739.