People often nap in between. But is napping good or bad? A new study shows that napping on a regular basis is associated with higher risks for high blood pressure and stroke.
The researchers in China claimed this as the first study to use both observational analysis of participants over a long period of time and Mendelian randomization – a genetic risk validation to investigate whether frequent napping was associated with high blood pressure and ischemic stroke.
The new research is published in Hypertension, an American Heart Association journal.
“These results are especially interesting since millions of people might enjoy a regular, or even daily nap,” says E Wang, Ph.D., M.D., a professor and chair of the Department of Anesthesiology at Xiangya Hospital Central South University, and the study’s corresponding author.
NAPPING; METHOD USED
The information fromUK Biobank was used for the analysis. UK Biobank recruited more than 500,000 participants between the ages of 40 and 69 who lived in the United Kingdom between 2006 and 2010. They regularly provided blood, urine and saliva samples, as well as detailed information about their lifestyle. The daytime napping frequency survey occurred 4 times from 2006 – 2019 in a small proportion of UK Biobank participants.
Wang and the team excluded records of people who had already had a stroke or had high blood pressure before the start of the study. This left about 360,000 participants to analyze the association between napping and first-time reports of stroke or high blood pressure, with an average follow-up of about 11 years. Participants were divided into groups based on self-reported napping frequency: “never/rarely,” “sometimes,” or “usually.”
- A higher percentage of usual-nappers were men, had lower education and income levels, and reported cigarette smoking, daily drinking, insomnia, snoring and being an evening person compared to never- or sometimes-nappers;
- People who usually nap had a 12% higher likelihood of developing high blood pressure and 24% higher likelihood of having a stroke;
- Participants younger than age 60 who usually napped had a 20% higher risk of developing high blood pressure compared to people the same age who never napped. After age 60, usual napping was associated with 10% higher risk of high blood pressure compared to those who reported never napping;
- About three-fourths of participants remained in the same category throughout the study;
- The Mendelian randomization result showed that If napping frequency increased by one category (from never to sometimes or sometimes to usually) high blood pressure risk increased 40%. Higher napping frequency was related to the genetic propensity for high blood pressure risk.