Death by Napping? The Frightening Link to High Blood Pressure and Increased Stroke Risk – The Mahathian Post

A study by the American Heart Association shows a link between frequent naps and high blood pressure.

• Frequent or usual daytime naps were associated with a 24% higher risk of stroke and a 12% higher risk of developing high blood pressure in adults, compared with no naps.
• Experts say that napping, while not unhealthy, could be a sign of poor sleep quality.
• A higher percentage of frequent nappers were men, had lower education and income levels, and reported drinking daily, smoking cigarettes, having insomnia, snoring, and being an evening person compared to people who reported napping sometimes or never make.
• The result of Mendelian randomization shows that the risk of hypertension increased by 40% when the frequency of naps was increased by one category (from never to sometimes or sometimes to usually).

According to a new study published in July 25, 2022 hypertensiona journal of the American Heart Association, regular naps are associated with a higher risk of high blood pressure and stroke.

For the research, scientists in China examined whether frequent napping could be a potential causal risk factor for hypertension and/or stroke. It is the first study to examine whether frequent napping is linked to hypertension and ischemic stroke, using both observational analysis of participants over a long period of time and Mendelian randomization – a genetic risk validation.

“These results are particularly interesting because millions of people could take naps regularly or even daily,” says Dr. E. Wang, Professor and Chair of the Department of Anesthesiology at Xiangya Hospital Central South University, and the corresponding author of the study.

For the study, the researchers used information from the UK Biobank. This large biomedical database and research resource contains anonymised genetic, lifestyle and health information from half a million UK participants. Between 2006 and 2010, the UK Biobank recruited more than 500,000 participants aged 40-69 living in the UK. The participants provided regular blood, urine and saliva samples as well as detailed information about their lifestyle. The nap frequency survey was conducted four times from 2006 to 2019 among a small proportion of UK Biobank participants.

Wang’s team excluded records from people who had already had a stroke or had high blood pressure before the study began. That left about 360,000 participants to analyze the association between napping and first reports of stroke or high blood pressure, with a median follow-up of about 11 years. Participants were divided into three groups based on self-reported nap frequency: never/rarely, sometimes, or usually.

The study found:

• A higher percentage of habitual nappers were males, had lower education and income levels, and reported drinking daily, smoking, snoring, having insomnia, and being an evening person compared to never or sometimes napping;
• People who normally napped were 12% more likely to develop high blood pressure and 24% more likely to have a stroke compared to people who reported never napping;
• Participants under the age of 60 who normally napped had a 20% higher risk of developing high blood pressure compared to their peers who never napped. After age 60, habitual napping was associated with a 10% higher risk of high blood pressure than those who reported never napping;
• About three quarters of the participants stayed in the same sleep category throughout the study;
• The result of Mendelian randomization showed that the risk of high blood pressure increased by 40% when the frequency of naps was increased by one category (from never to sometimes or sometimes to usually). A higher frequency of naps was linked to a genetic predisposition to risk of high blood pressure.

“This may be because, while napping is not in itself harmful, many people who nap do so because they sleep poorly at night. Poor nighttime sleep is associated with poorer health, and naps are not enough to offset it,” said Michael A. Grandner, Ph.D., MTR, a sleep expert and co-author of the new American Heart Association article Life’s Essential 8 Cardiovascular Health Scorewho added the sleep duration in June 2022 as 8^th Metric used to measure optimal heart and brain health. “This study echoes other findings, which generally show that more naps appear to reflect an increased risk of heart health and other problems.” Grander is director of the Sleep Health Research Program and the Behavioral Sleep Medicine Clinic and an associate professor of psychiatry at the University of Arizona at Tucson.

The researchers recommend further investigation into the links between healthy sleep patterns, including daytime naps, and heart health.

Several important limitations of the study should be considered. Scientists only tracked the number of naps per day, not the duration, so there’s no information on how or if napping length affects blood pressure or stroke risk. Additionally, nap frequency was self-reported without objective measurements, making estimates unquantifiable. In addition, the research participants were predominantly middle-aged and elderly of European descent, so the results may not be generalizable. Finally, scientists have not yet discovered the biological mechanism for the effect of napping on blood pressure regulation or stroke.

Reference: “Association of Nap frequency with hypertension or ischemic stroke supported by prospective cohort data and Mendelian randomization in predominantly middle-aged European subjects” by Min-jing Yang, Zhong Zhang, Yi-jing Wang, Jin-chen Li, Qu-Lian Guo, Xiang Chen and E. Wang, July 25, 2022, hypertension.
DOI: 10.1161/HYPERTENSIONAHA.122.19120

Co-authors are Min-jing Yang, MD; Zhong Zhang, Ph.D., MD; Yi-jing Wang; MD; Jin-chen Li, Ph.D.; Qu-lian Guo, Ph.D., MD; Xiang Chen, Ph.D., MD

The National Key Research and Development Program of China supports this research financially.