The impact of napping on heart health has to date been hotly contested.
Many of the published studies on the topic have failed to consider napping frequency or focused purely on cardiovascular disease deaths or compared regular nappers with those not opting for a mini siesta, say the researchers.
In a bid to try and address these issues, they looked at the association between napping frequency and average nap duration and the risk of fatal and non-fatal cardiovascular disease ‘events’, such as heart attack, stroke, or heart failure, among 3,462 randomly selected residents of Lausanne, Switzerland.
Each participant was aged between 35 and 75 when recruited between 2003 and 2006 to the CoLaus study.
The research has been looking at the factors behind the development of cardiovascular disease.
Participants’ first check-up took place between 2009 and 2012, when information on their sleep and nap patterns in the previous week was collected, and their health was then subsequently monitored for an average of five years. More than half (58 per cent, 2014) of the participants said they didn’t nap during the previous week, while around one in five (19 per cent, 667) said they took one to two naps. Around one in ten (12 per cent, 411) said they took three to five naps, while a similar proportion (11 per cent, 370) said they took six to seven.
Frequent nappers (3-7 naps a week) tended to be older, male and smokers. They also tended to weigh more and to sleep for longer at night than those who said they didn’t nap during the day.
And they reported more daytime sleepiness and more severe obstructive sleep apnoea – a condition in which the walls of the throat relax and narrow during sleep, interrupting normal breathing.
During the monitoring period, there were 155 fatal and non-fatal cardiovascular disease ‘events’.
Occasional napping – once to twice weekly – was associated with an almost halving of attack/stroke/heart failure risk (48 per cent) compared with those who did not nap at all.
This association held true after taking account of potentially influential factors such as age and nighttime sleep duration, as well as other cardiovascular disease risks such as high blood pressure and cholesterol.
And it did not change after factoring in excessive daytime sleepiness, depression and regularly sleeping for at least six hours a night. Only older age (65+) and severe sleep apnoea affected it.
The authors of the study published online in the journal Heart, said: “The study of napping is a challenging, but also a promising field with potentially significant public health implications. While there remain more questions than answers, it is time to start unveiling the power of naps for a supercharged heart.”