David Nield, Science Alert, Sep 11, 2019
Researchers monitored 3,462 volunteers in Switzerland for an average of a little over five years, getting them to note down their napping habits and then comparing those habits with incidents of cardiovascular disease (CVD).
The figures showed that occasional napping - once or twice a week - was associated with a lower risk of heart attack, heart failure or stroke compared with not napping at all.
That association disappeared with more frequent napping though, and the link wasn't present in the over 65s (perhaps due to more complex health issues).
"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," a pair of psychiatry researchers who weren't involved in the study write in an accompanying editorial published in the journal Heart.
This highlights something previous studies on this subject have rarely looked at - how regularly naps are taken.
Before you go ahead and lock in a bunch of scheduled naps into your agenda, we should emphasise that this study was observational, and therefore doesn't prove cause and effect.
That said, the researchers did adjust for a few factors, including things like daytime sleepiness and nighttime sleep duration. The naps might not be directly responsible for the variation in CVD incidents.
It's possible, for example, that those who stick to one or two naps per week have healthier and more organised lifestyles - and that way of living is affecting CVD risk rather than getting forty winks every so often.
Other limitations to bear in mind are that the study relied on self-reporting as far as the number of naps went, and there were relatively few CVD events (155) in total, which makes it more difficult to draw broad conclusions.
Nevertheless, the research adds some useful data to what continues to be a fascinating topic - the link between naps and cardiovascular health. Some previous studies have shown that naps can reduce the risk of CVD, while others have reported the opposite.
Could nap frequency help explain some of the disparity in these results? That's what the researchers behind the new study are suggesting - and they want to see the number of weekly naps included in the analysis of future studies.
In case you're wondering, around one in five of the participants, who were aged between 35 and 75 when the study started, napped once or twice a week. A little over half (58 percent) reported that they didn't nod off in the daytime at all.
For those who do enjoy a bit of daytime snoozing, the signs continue to be encouraging. Other studies have shown links between naps and improved cognitive functioning, a boost in mood, and better emotional control.
And while nobody is promising that a couple of naps a week will drastically reduce your risk of heart disease, this latest study is an interesting addition to the field.
"While it remains premature to conclude on the appropriateness of napping for maintaining optimal heart health, the findings .. offer some reassurance that the answer is probably more than a simple 'yes' or 'no', and that we have much more to learn about napping," states the editorial.
The research has been published in Heart.
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