Long Naps Could Be Bad for Your Health

Snoozes are linked to a greater risk of cardiovascular disease.

Teen napping on the sofa with dog
Research has found naps might help lower blood pressure. Justin Paget / Getty Images

With everything going on right now in the world, your job, your family — and really just life — is it any wonder you're exhausted? If you find some time between meetings or after lunch, it may be tempting to take a nice, long nap.

Don't do it, say the authors of a new study presented at the European Society of Cardiology Congress in late August.

"Daytime napping is common all over the world and is generally considered a healthy habit," said study author Dr. Zhe Pan of Guangzhou Medical University, China, in a news release. "A common view is that napping improves performance and counteracts the negative consequences of 'sleep debt'. Our study challenges these widely held opinions."

Pan and his team analyzed existing research to look at the relationship between napping and the risk of death, including specifically cardiovascular disease.They analyzed 20 studies involving at total of 313,651 people. In that research, 39% of participants said they took naps.

"In our study, long naps (more than 60 minutes) were associated with a 30% greater risk of all-cause death and 34% higher likelihood of cardiovascular disease compared to no napping," Pan told Treehugger. "When night-time sleep was taken into account, long naps were linked with an elevated risk of death only in those who slept more than six hours per night."

The researchers found that short naps of less than an hour did not appear to put the nappers at risk of developing cardiovascular disease.

To Nap or Not to Nap

There has been conflicting research about naps. Some research says napping can offer a variety of benefits from memory boosts to alertness. It can make up for sleep loss, of course, but it may also lower blood pressure. A study published in the Journal of Applied Physiology found that napping is associated with a 37% reduction in coronary mortality. Researchers aren't sure if the benefit is due to actually napping, being in a reclined position, or having the expectation of a nap.

Other research suggests that if you nap during the day, it's more difficult to fall asleep at night. That's why sleep experts often suggest a quick 15-20 minute snooze if you are going to rest during the day.

Pan's team found a connection between napping, night-time sleep, and potential harmful side effects.

"We found that night sleep duration may be a potential confounder in the relationship between nap and all-cause mortality. Long sleep duration was negatively associated with frequency of napping and napping predicted shorter nocturnal sleep duration and poorer self-reported sleep quality that night," Pan told Treehugger. "Participants who took a long nap (more than 60 minutes/day) and had more than 6 hours of night sleep were associated with a significantly higher risk of all-cause mortality." 

The researchers found that naps of any duration were linked with a 19% elevated risk of death. Women had a 22% greater likelihood of death with napping compared to no napping. In older participants, the risk increased by 17% when they took naps.

It's still unclear why napping affects the body, Pan says.

"There are several mechanisms behind the association between napping and all-cause mortality and cardiovascular disease. Long nap duration was considered negatively associated with physical indicators like higher depression rate, older age, less physical activity, and poor mental health status, which all were important predictors of all-cause mortality," he says. "Also, levels of inflammatory marks, such as C-reactive protein and interleukin-17 have been reported to increase in subjects who took long naps."

If all this talk of napping makes you want to hit your pillow, be sure you set an alarm and make it quick.

"If you want to take a siesta, our study indicates it's safest to keep it under an hour," Pan says. "For those of us not in the habit of a daytime slumber, there is no convincing evidence to start."