Frequent Naps Increase Risk of High Blood Pressure, Stroke

For some, there is nothing more refreshing than taking a nap. However, research published today in Hypertension, an American Heart Association journal, found that regular naps are associated with greater risks for high blood pressure and stroke.

“These results are especially interesting since millions of people might enjoy a regular, or even daily nap,” said the study’s corresponding author E Wang, PhD, MD, a professor and chair of the Department of Anesthesiology at Xiangya Hospital Central South University, in a press release.

During the study, the investigators combined Mendelian randomization and long-term observational analysis to assess any relationship between frequent napping, high blood pressure, and ischemic stroke. Using the UK Biobank, which is a biomedical database containing anonymous genetic, lifestyle, and health information from United Kingdom participants, the investigators recruited more than 500,000 participants between the ages of 40 to 69 years living in the United Kingdom between 2006 to 2010.

Participants in the UK Biobank offered blood, urine, and saliva samples to the bank, along with self-reported lifestyle information, such as reported naps. Investigators then used this information to analyze the association between first-time stroke, or high blood pressure, over a period of 11 years. Investigators ultimately analyzed 360,000 people out of the more than 500,000 included because they did not want to account for anyone that had previously suffered from stroke or high blood pressure.

Based on self-reported napping frequency under the categories of ‘never/rarely,’ ‘sometimes,’ or ‘usually,’ investigators divided participants into groups for the purposes of analysis. Based on the results, the data showed that men comprised the higher percent of ‘usually’ responses regarding nap frequency. Other higher percentages of ‘usual’ included those of lower education and income levels, those who smoked cigarettes and participated in daily drinking, and those who experienced insomnia, snoring, or were an evening person.

In general, the results showed that people who regularly napped were 12% more likely to develop high blood pressure and 24% more likely to have a stroke. Additionally, participants below the age of 60 years were 20% more at risk of high blood pressure than those who reported never napping, and participants older than 60 years who reported taking naps were associated with 10% higher risk of blood pressure than non-nappers. Further, higher napping frequency was related to genetic tendency of high blood pressure risk, according to the Mendelian randomization results.

Michael A. Grandner, PhD, MTR, a sleep expert and co-author of the American Heart Association’s new Life's Essential 8™ cardiovascular health score, said that the results may reflect the harm of poor sleep at night or poor health, which cannot be mediated by a nap.

"This study echoes other findings that generally show that taking more naps seems to reflect increased risk for problems with heart health and other issues,” Grandner said in the press release.

The study authors noted that considerable limitations in the study included age and ethnicity, which were comprised of mostly middle-aged and elderly Europeans, and investigators were limited to nonquantifiable estimates through self-reported results. Nap duration was also not accounted for, and not enough research on the biological mechanisms of daytime napping exist to assess its effect on stroke or blood pressure.

Reference

Study shows link between frequent naps and high blood pressure. EurekAlert. July 25, 2022. Accessed July 25, 2022. https://www.eurekalert.org/news-releases/959311