I don’t blame you for being confused. A study from Switzerland published in September 2019 found that daytime napping can reduce the risk of having a heart attack – unless you do too much of it. The Swiss researchers investigated the link between how frequently people nap, how long their naps typically last, and how these factors affect the risk of heart attack, heart failure, and stroke. They looked at the napping habits of 3,462 men and women between the ages of 35 and 75 who were taking part in a study examining factors behind the development of cardiovascular disease. Information on these individuals napping patterns from the week before their first checkup was collected between 2009 and 2012. More than half reported that they didn’t nap at all during the previous week. Another 19 percent said they took one to two naps, one in 10 said they took three to five naps while 11 percent reported taking six to seven naps.
During the following five years, 155 study participants had cardiovascular “events,” some of which were fatal. The researchers reported that napping once or twice a week was linked with nearly half the risk of having a heart attack, heart failure, or stroke compared with those who didn’t nap at all. This held true even after factoring in age, and other cardiovascular disease risks, such as high blood pressure or high cholesterol levels. The risks didn’t change after the researchers considered excessive daytime sleepiness, depression, and regularly getting at least six hours sleep at night. No connections to cardiovascular disease were seen for naps that lasted for as little as five minutes to one hour or more.
Because the study was observational, it couldn’t prove cause and effect. Also, the information collected relied on the recollection of study participants and could not be objectively confirmed. Even so, nap frequency appeared to be the critical factor.
The most frequent nappers were older men who were overweight and smoked. These men also reported sleeping longer at night and experiencing more daytime sleepiness than others in the study who didn’t nap. And they were more likely than others in the study to have sleep apnea, a serious disorder that causes interruptions of breathing (for at least 10 seconds) during sleep.
Initially, the researchers concluded that frequent nappers had a higher risk for cardiovascular disease, but when they accounted for sociodemographic, lifestyle and other factors, the increased risk disappeared.
In an editorial commenting on the study, two physicians from the University of California at San Francisco noted that research about napping is “hampered by the absence of a gold standard for defining and measuring naps,” making it premature to conclude how appropriate napping is for maintaining optimal heart health.
Aside from the potential benefits to heart health, I’m a big fan of napping. I used to worry about the need to nap and would often fight off the impulse when I had work to do. I’ve since learned that people who nap generally enjoy better mental health and mental efficiency. They may also sleep better at night. Now, if I feel the need to nap and have the opportunity, I just take one, and usually wake up feeling refreshed after 10 or 20 minutes.
Andrew Weil, M.D.
Nadine Häusler et al, “Association of napping with incident cardiovascular events in a prospective cohort study.” Heart, September 9, 2019 DOI: 10.1136/heartjnl-2019-314999