LAUSANNE, Switzerland — A tranquil nap in the afternoon can be a great way to break up the day and add some pep to your step for the rest of your daily routine. Now, researchers in Switzerland have found another reason why you should consider enjoying a regular daytime snooze: taking a daytime nap once or twice a week may lower your risk of suffering a heart attack or stroke.
Interestingly, the study authors note that the period of time spent napping didn’t seem to influence this benefit, nor did napping any more than twice per week.
For the study, researchers analyzed the association between frequency and duration of naps with the risk of fatal and non-fatal serious cardiovascular disease events like heart attacks and strokes in 3,462 randomly selected residents of Lausanne, Switzerland. Participants were between 35 and 75 years old, and recruited between 2003 and 2006.
Following their initial enrollment, each participant had their first check-up between 2009 and 2012. Then, researchers recorded information on participants’ sleep and nap patterns, and monitored their health outcomes for an average of five years.
In all, more than half (58%) of the participants said they usually didn’t nap on a week-to-week basis; 19% said they took one to two naps per week; 12% said they took between three and five naps; and 11% said they dozed off at least six or seven times weekly.
The most frequent nappers were mostly older overweight men with a smoking habit, and tended to sleep longer at night than those who said they didn’t nap during the day. This frequent napping group also reported more daytime sleepiness and more severe obstructive sleep apnea.
During the monitoring period,155 fatal and non-fatal cardiovascular disease events were recorded. Those who reported occasional (once to twice weekly) napping reduced their cardiovascular disease event probability by 48% compared to those who didn’t nap at all. This association still held true even after controlling for other influential factors, such as patient age, nighttime sleep duration, high blood pressure, and high cholesterol. Furthermore, these findings didn’t fluctuate after factoring in daytime fatigue, depression, and regularly sleeping for at least six hours a night.
The only factors that did affect the heart benefits of napping were old age (65+) and sleep apnea. In fact, there was an initial observed increase in cardiovascular risks among frequent nappers, but researchers say these results were virtually disproven after taking into account factors like age and conditions like sleep apnea.
Researchers also noted no difference in the rate of cardiovascular events depending on nap duration, ranging from as short as five minutes to over one hour.
The study’s authors caution this is an observational study, meaning it can not definitively establish cause. Furthermore, the data used relied on participants’ subjective memories and ability to recall their napping habits, leaving open the possibility for error.
“While the exact physiological pathways linking daytime napping to [cardiovascular disease] risk is not clear, [this research] contributes to the ongoing debate on the health implications of napping, and suggests that it might not only be the duration, but also the frequency that matters” comments Dr. Yue Leng and Dr. Kristine Yaffe, of the University of California at San Francisco, in a release. “The study of napping is a challenging but also a promising field with potentially significant public health implications. While there remain more questions than answers, it is time to start unveiling the power of naps for a supercharged heart.”
The study is published in the scientific journal Heart.