The latest research has found that having a daytime nap, one to two times a week, can reduce cardiovascular disease risk. But no link was present for either greater duration or frequency of naps. The journal Heart has published these results.
Napping duration and frequency
Many studies in the past have studied the effect of napping on cardiovascular disease risk. But these studies haven’t considered napping frequency or stressed purely on CVDs. While, in this study, the research team has looked at the link between average nap duration and napping frequency.
Also, this study has analyzed the risk of fatal and non-fatal disease events, such as stroke, heart attack, and heart failure. The team has randomly selected 3462 people from Lausanne, Switzerland. Where each person had an age between 35 and 75 when included in the CoLaus study between 2003 and 2006.
This study has looked at the factors behind cardiovascular disease risk. The first check-up took place in 2009 – 2012. Where the team collected the info about sleep and nap pattern in the last week. Later, the team monitored the health of the participants for about 5 years. Nearly 58% of the people stated that they didn’t take a nap during the last week.
About 19% (one in five persons) said they had one to two naps. The frequency of the nap was three to five in 12% of the participants. While it was 6 – 7 in a similar proportion (about 11%). Frequent nappers (who took 3 – 7 naps per week) were male, older, and smokers.
They also tend to weigh more and sleep for a longer period at night than those who didn’t have a nap during the daytime. And stated increased daytime sleepiness and more severe obstructive sleep apnea. In sleep apnea, the thorax walls relax and narrow during sleep, which can interrupt the normal breathing process.
How nap affects heart health of a person
During the observation period, there was an increase in cardiovascular disease risk in people who didn’t take a nap. That was indicated by 155 fatal and non-fatal CVD events. While, occasional napping, one to two times per week, was linked with lower cardiovascular disease risk.
There was a 48% reduction in the risk of stroke, heart attack, or heart failure in contrast to those who didn’t nap at all. Later, the team looked at the potential influencing factors, like age, sleep duration during the night, as well as other CVD risks, such as high blood pressure or cholesterol levels. And found the link as true.
The association was the same after factoring infrequent daytime sleepiness, regular sleep for at least 6 hours per night and depression. But severe sleep apnea and 65+ age have affected this association. The 67% increase in CVD risk among frequent nappers virtually disappeared after considering these factors.
On the other hand, no association with CVD events was present for nap length above 5 minutes to 1 hour. As this is an observational study and info on sleep patterns and nap relied on personal recall, the study can’t establish a cause.
But the frequency of nap can help explain the different conclusions about the effects of nap on heart health. Moreover, the lack of a gold standard to define and measure naps has hindered the research in this area. And has made it premature to deduce on the suitability of napping for maintaining heart health.