The study, conducted by Swiss researchers at the Lausanne University Hospital in Switzerland, was based on data from almost 3,500 people living in the country.
The participants, aged between 35 and 75, were asked to report their nap frequency and daily nap duration for more than five years. None of the participants were excessively sleep-deprived or had any signs of heart disease.
"We looked at healthy adults and found that people who take occasional naps - once or twice a week - had a lower risk for cardiovascular disease compared to people who were not napping at all," Nadine Häusler, lead author of the study, is quoted as saying by NBC News.
Fifty-eight percent of participants said they rarely ever took daytime naps, whereas about 10% said they took naps almost every day.
Twenty percent of participants took naps one to two times every week, which was the only nap frequency linked to a 48% lower chance of cardiovascular disease. Nap duration, however, did not appear to be linked to any health benefits.
"Our best guess is that a daytime nap just releases stress from insufficient sleep," Häusler speculated.
"It could be that these people who nap once to twice a week are those who make napping a priority, because they know they don't sleep enough during the week," commented Céline Vetter, an assistant professor at the University of Colorado Boulder who studies sleep, according to NBC. Vetter was not involved in the study.
However, the researchers also noted that one of the major limitations of the study is that the participants self-reported nap frequency and duration. Additional research is needed to conclusively draw any results regarding daytime nap benefits.
