Long naps tied to increased stroke risk

Long naps tied to increased stroke risk

Taking long naps during the day, sleeping longer at night, and having poor sleep quality were associated with increased risk for stroke, according to a study published in Neurology, the medical journal of the American Academy of Neurology.

“These results highlight the importance of moderate napping and sleeping duration and maintaining good sleep quality, especially in middle-age and [among] older adults,” Xiaomin Zhang, MD, PhD, of Huazhong University of Science and Technology in Wuhan, China, said in a press release.

Zhang and colleagues conducted a prospective cohort study evaluating stroke incidence in 31,750 adults with an average age of 61.7 years. Participants, who were retired employees from a company in China, completed baseline medical examinations and questionnaires at enrollment and during follow-up.

Researchers found that sleeping 9 hours or longer per night was associated with a greater risk for stroke (HR = 1.23; 95% CI; 1.07-1.41) compared to sleeping 7 to 8 hours per night.

Compared with napping for 1 to 30 minutes during the day, napping more than 90 minutes was associated with a greater risk for stroke (HR = 1.25; 95% CI; 1.03-1.53).

Researchers said poor sleep quality was associated with a 29% increase in risk for any stroke compared with good sleep quality. The risk for ischemic stroke was 28% higher and the risk for hemorrhagic stroke was 56% higher in those who reported poor sleep quality.

Zhang and colleagues found that the risk for stroke was higher among those who reported both sleeping 9 hours or longer each night and took naps 90 minutes or longer during the day (HR = 1.85; 95% CI 1.28-2.66) compared with those who slept 7 to 8 hours per night and napped 1 to 30 minutes during the day.

Additionally, they found that those who reported sleeping 9 hours or longer each night and having poor sleep quality had a higher risk for stroke (HR = 1.82; 95% CI 1.33-2.48) compared with those who reported sleeping 7 to 8 hours per night and having good sleep quality.

The researchers noted that their study shows an association, not causation, between long nap and sleep duration and 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,” Zhang said in the release. "In addition, long napping and sleeping may suggest an overall inactive lifestyle, which is also related to increased risk of stroke.” – by Erin Michael

Stroke: Excessive sleep may raise risk by 85%

Stroke is one of the leading causes of death and disability worldwide and in the United States, specifically. New research finds that excessive sleep considerably raises the risk of this cardiovascular problem.

New research suggests that people who take long naps in the day may be at a higher risk of stroke.

Globally, 15 millionTrusted Source people experience a stroke each year. Almost 6 million of these people die as a result, and 5 million go on to live with a disability.

In the U.S., over 795,000Trusted Source people have a stroke each year.

The list of traditional risk factorsTrusted Source for stroke is long, ranging from elements of lifestyle, including smoking, to preexisting conditions, such as diabetes.

More recently, researchers have started exploring sleep duration as another potential risk factor. Some studiesTrusted Source have found that either too much or too little sleep can increase the risk of cardiovascular events, including stroke.

According to these findings, regular sleep deprivation and sleep for more than 7 hours per night are each associated with a higher risk of stroke.

Now, a study appearing in the journal Neurology finds an association between daytime naps, excessive sleep, and stroke risk.

Dr. Xiaomin Zhang, from Huazhong University of Science and Technology, in Wuhan, China, is the corresponding author of the paper that details this study.

85% higher risk in long sleepers, nappers
Dr. Zhang and the team collected information from 31,750 people in China. None of the participants — who were 62 years old, on average — had a history of stroke or any other serious health condition at the start of the study.

The participants answered questions about their sleeping patterns and napping habits, and the researchers clinically followed the group for an average of 6 years.

The team found that 8% of the participants were in the habit of taking naps that lasted longer than 90 minutes, and 24% reported sleeping for at least 9 hours each night.

Over the study period, there were 1,557 strokes among the participants. Those who slept for 9 or more hours per night were 23% more likely to experience a stroke than those who regularly slept only 7–8 hours each night.

People who got less than 7 hours of shuteye or 8–9 hours had no higher risk of stroke than those who slept 7–8 hours.

Importantly, people who both slept for longer than 9 hours and napped for more than 90 minutes per day had an 85% higher risk of stroke than those who slept and napped moderately.

Finally, sleep quality seemed to play a role — people who reported poor sleep quality were 29% more likely to have a stroke than those whose sleep quality was reportedly good.

These results continued to be significant after adjusting for potential confounders, such as hypertension, diabetes, and smoking.

"These results highlight the importance of moderate napping and sleeping duration and maintaining good sleep quality, especially in middle-age and older adults."
-Dr. Xiaomin Zhang

Study limitations and potential mechanisms
The researchers acknowledge some limitations to their work, as well as the fact that more research is necessary.

First, because the study was observational, it cannot prove causality. Second, the research did not account for sleep apnea or other sleep disorders that may have influenced the results.

Third, self-reported data is not as reliable as data recorded by researchers who observe participants' sleep.

Finally, the results may only apply to older, healthy Chinese adults and not to other populations.

"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," explains Dr. Zhang.

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