A study published in July 2022, reports that people who take regular daytime naps might be more at risk for hypertension and stroke.
Around one-third of adults in the United States take a daytime nap, with many indicating that naps relax and recharge them. However, napping on a regular basis is associated with higher risks for high blood pressure and stroke, according to new research published in the journal, Hypertension. Researchers in China used information from the UK Biobank, an extensive biomedical database and research resource. The site contains genetic, lifestyle, and health information from more than 500,000 people.
In this study, research participants were between the ages of 40 and 69 and lived in the United Kingdom between 2006 and 2010. Each person provided blood, urine, and saliva samples regularly. The scientists did not have access to names or personal information. Between 2006 and 2019, participants were asked about daytime napping four times. After ruling out people who were previously diagnosed with high blood pressure or had had a stroke before the start of the study, the scientists had information for 360,000 individuals. The average follow-up was 11 years after the beginning of the study.
The researchers divided the participants into three groups based on napping frequency: never/rarely, sometimes, or usually.
The study findings included:
- Most “usual nappers” were men, had lower education and income levels, smoked cigarettes, drank regularly, snored, had insomnia, and reported being an evening/night person.
- Compared to people in the never/rarely category, people who usually napped had a 12 percent higher likelihood of developing high blood pressure and a 24 percent higher chance of stroke.
- Participants under 60 who reported usually napping had a 20 percent higher risk of developing hypertension than those who never or rarely rested.
“It is important to note that a majority of the ‘usual-nappers’ reported other conditions or lifestyle factors that could contribute to high blood pressure, says Dr. Samuel Werner DO, a family medicine specialist and an adjunct assistant professor at the Rowan University School of Osteopathic Medicine in New Jersey. We have known for decades that smoking contributes to cardiovascular issues and people with untreated sleep apnea do not get quality sleep because they wake, often without knowing it, throughout the night. Previous studies have found that higher BMIs, which can in part, be caused by drinking, can increase the risk for high blood pressure and stroke,” said Werner.
Around three-fourths of the participants remained in the same category throughout the study period. However, for those whose napping frequency increased by one category, such as from “sometimes” to “usually” napping, high blood pressure risk increased by 40 percent. The researchers believe that it is not necessarily napping that leads to high blood pressure or stroke but that many people who nap do so because of poor nighttime sleep.
Naps do not make up for missed or interrupted sleep during the night. Researchers say it is poor sleep at night that is associated with poorer health.
“Ideally, people should get seven hours of uninterrupted sleep at night. This amount provides the most benefit to cardiovascular health,” Dr. Andrew M Freeman, FACC, FACP, a cardiologist at National Jewish Health in Denver, told Healthline. “High blood pressure is widespread. Your chance of death doubles for every 20 points over the 120 mark when measuring blood pressure.
Limitations of the study include:
- Researchers did not ask or keep track of nap durations, potentially influencing health outcomes.
- Most participants were middle-aged or older adults of European descent and the results might not be transferable to other groups of people.
- Nap frequency was self-reported, making it potentially inaccurate.