People who sleep more than nine hours a night, or have long daytime naps have an increased risk of stroke, according to new research.

The Chinese study, published in the journal Neurology, examined the sleep habits of 31,750 healthy adults, with an average age of 61.7 years, over a six-year period.

In that time there were 1,438 definite and 119 probable stroke cases.

Those who said they had slept nine or more hours a night were 23% more likely to go on to have a stroke than people who slept seven to less than eight hours per night.

Regular daytime nappers who slept for more than 90 minutes were 25% more likely to later have a stroke than people who napped for under half an hour.


People who were both long nappers and long sleepers were 85% more likely to later have a stroke than people who were moderate sleepers and nappers.

People who reported poor quality of sleep were 29% more likely to later have a stroke than people who felt they had

slept well.

And those who were long sleepers who also had poor sleep quality were 82% more likely to later have a stroke.

Study author Xiaomin Zhang, of Huazhong University of Science and Technology in Wuhan, China, said: "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 unfavourable changes in their cholesterol levels and increased waist circumferences, both of which are risk factors for stroke.

"In addition, long napping and sleeping may suggest an overall inactive lifestyle, which is also related to increased risk of stroke."

Around 100,000 strokes occur each year in the UK.