Sleeping nine hours or more a night increases chance of stroke, study claims

12 Dec 2019

Image: © Tracy King/

A study in China has linked lengthy sleeping and napping to an increased risk of stroke, but authors admit more research is needed.

Lying in, long midday naps and disrupted sleep are all linked to an increased risk of stroke of up to 85pc, research has suggested.

People who sleep more than nine hours at night or who regularly nap for longer than 90 minutes are up to a quarter more likely to have a stroke than those who get less shut-eye. Researchers from China also found that people who reported poor quality of sleep were 29pc more likely to later have a stroke than people who felt they had slept well.

They asked 31,750 healthy Chinese adults, with an average age of 61.7 years, about their sleep and nap habits. There were 1,438 definite and 119 probable stroke cases during an average follow up period of six years.

Those who said they had slept nine or more hours a night were 23pc 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 25pc more likely to later have a stroke than people who napped for under half an hour.

Just an inactive lifestyle?

People who were both long nappers and long sleepers were 85pc more likely to later have a stroke than people who were moderate sleepers and nappers. And those who were long sleepers and also had poor sleep quality were 82pc 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.”

The study is published in the journal Neurology.

– PA Media