Worldwide, more than 15 million people are found to experience a stroke each year, which results in more than 5 million people living with a disability and over 6 million deaths. And in the United States, more than 795,000 people have a stroke each year.
There are a number of factors responsible for causing a stroke, such as unhealthy lifestyle, smoking, preexisting medical conditions, such as hypertension and diabetes. Researchers have also found that the duration of sleep plays a key role in determining the potential risk factor of stroke.
While some studies have found that insomnia or sleep deprivation could increase the risk of stroke, one study has claimed that excessive sleeping is associated with an increased risk of stroke.
A new Chinese study, published in the journal of Neurology, has found an association between excessive daytime napping and sleep, and increased risk of stroke.
A team of researchers led by Dr. Xiaomin Zhang from Huazhong University of Science and Technology, China, gathered information from over 31,750 people in China.
The participants, who were in their 60s, had no history of stroke or any other serious medical condition at the start of the study. They were asked questions about their napping habits and sleeping patterns.
The researchers followed them up for a period of 6 years and found that there 1,557 participants who had a stroke. They noted that participants who slept for more than 9 hours a night were 23 percent more likely to have a stroke than those who slept for 7 to 8 hours a night.
More importantly, participants who slept for more than 9 hours and napped for over 90 minutes a day had an 85 percent increased risk of experiencing a stroke. In addition, volunteers who reported poor sleep quality were 29 percent more likely to experience a stroke.
Dr. Zhang said, “These results highlight the importance of moderate napping and sleeping duration and maintaining good sleep quality, especially in middle-age and older adults.”
However, there were a few limitations to the study. The study was observational so it could prove the exact cause. It was conducted only on older people and not on healthy and younger people.
“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,” explained Dr. Zhang. “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 and sleeping may suggest an overall inactive lifestyle, which is also related to increased risk of stroke,” the author added.