Sleeping too much or not enough is not good for health, this issue seems to have gained consensus in the scientific community. But what about the naps that many of us allow ourselves in the afternoon to make up for after a rough night or to interrupt a busy day? Here, opinions are more divergent. Two studies published on the same day but in two different publications analyzed the health effects of naps. Although different in their methodology, they come to the same conclusion: people who take naps are more likely to have health problems, including cardiovascular problems.
The nap, the enemy of the heart?
The first study was done by the American Heart Association and published in its journal. It was based on Swedish research that has been collecting health data since the 1960’s. Comparing a group of people with a similar profile, those taking a nap lasting between 1 and 30 minutes are at an increased risk of developing a cardiovascular problem. The risk is highest in people who sleep less than 7 hours a night and take naps longer than 30 minutes during the day. Scientists have observed the same trend in people who sleep well at night (between 7 and 9 a.m.), but this could not be statistically confirmed.
Indeed, another study found that naps were also harmful to health in people who sleep less than 6 hours a night. The real cause of cardiovascular disease seems to be lack of sleep at night — a deficit that naps, which do not replace a full sleep cycle, do not seem to fill. The second study, published in Hypertension, reported an increased risk of hypertension and stroke in middle-aged subjects who nap during the day.
Paul Leeson, a professor of cardiology at Oxford University, was cautious about the findings: “But it can be just a coincidence. There may be other health problems to explain why a person sleeps more during the day and why they have an increased risk of heart disease.” In addition, the biological mechanism that would explain this association between napping and cardiovascular disease risks is not known to date.