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WASHINGTON — A study published Monday by the American Heart Association Journals found a link between frequent naps and high blood pressure.
Science Daily reported that researchers in China examined whether frequent naps could be a potential causal risk factor for high blood pressure or stroke.
"This is 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," Science Daily reported.
The study's results are "especially interesting since millions of people might enjoy a regular, or even daily nap," said Dr. E. Wang, the study's author and a professor at the Department of Anesthesiology at Xiangya Hospital Central South University.
Researchers found that "frequent or usual daytime napping in adults was associated with a 12% higher risk of developing high blood pressure and a 24% high risk of having a stroke compared to never napping."
These findings lead experts to conclude that napping, though not unhealthy, may be a sign of poor sleep quality.
The study found that a higher percentage of frequent nappers were men, had lower education and income levels, and reported cigarette smoking, daily drinking, insomnia, snoring and being an evening person compared to people who reported napping sometimes or never.
"This may be because, although taking a nap itself is not harmful, many people who take naps may do so because of poor sleep at night. Poor sleep at night is associated with poorer health, and naps are not enough to make up for that," said clinical psychologist Michael Grandner.
Grandner directs the Behavioral Sleep Medicine Clinic at the Banner-University Medical Center in Tucson, Arizona, and was not involved in the study according to CNN.
The study also found that 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.
Though these findings are important, the study contains several notable limitations to consider. According to Science Daily, researchers only collected daytime napping frequency, not duration, so there is no information on whether the length of naps affects blood pressure or stroke risks.
"The study's participants were mostly middle-aged and elderly with European ancestry, so the results may not be generalizable," Science Daily reported. "Finally, researchers have not yet discovered the biological mechanism for the effect of daytime napping on blood pressure regulation or stroke."
