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If you are someone who frequently depends on naps to get you through the day, you may want to rethink that strategy.
A new study, published in the American Heart Association Journal Hypertension, has found that people who take naps regularly are at a higher risk of developing high blood pressure (hypertension) and ischemic stroke.
Dr. Mark Boulos, an associate professor of medicine at the University of Toronto, says that may be because frequently napping can be pointing to a larger issue.
“Napping to me is more of a flag that hey, listen, there's something else going on here overnight,” he adds. “They're not getting good quality sleep, or that they're not sleeping enough hours per night.”
For the study, researchers in China used data from the U.K. Biobank, a large biomedical database. The study looked at 360,000 participants between the ages of 40 and 69 who lived in the U.K. between 2006 and 2010.
Between 2006 and 2019, participants were asked about their daytime napping habits four times. Participants also regularly provided blood, urine and saliva samples.
The U.K. study excluded records of people who had previously suffered a stroke or had high blood pressure before the study began.
Duration of daytime naps was not collected
Researchers found that people who usually took a nap had a 12 percent higher likelihood of developing high blood pressure and a 24 percent higher likelihood of having a stroke than people who reported never taking a nap.
Participants younger than 60 years old who napped regularly were also at a 20 percent higher risk of developing high blood pressure compared to those who didn’t nap. Those who were over age 60 and napped frequently had a 10 percent higher risk of high blood pressure compared to those who reported never napping.
The study also notes most of the people in the study smoked cigarettes, drank daily had insomnia, snored, and were labelled as evening people.
Researchers do point out some limitations of the study. One is that the frequency of naps was collected, but the duration was not, which means there is no information on whether the length of a nap affects blood pressure or the risk of stroke.
The study also relied on people to report the naps themselves, without any “objective measurements.”
Lastly, most participants were middle-aged or older adults of European descent, so the results may not be “generalizable.”
What Canadian experts are saying about the study
After reading about the study, Dr. Charles Samuels says the information collected would not change the advice he gives to his patients when it comes to napping.
The medical director at the Centre for Sleep and Human Performance in Calgary says that’s because the “research methodologies don’t apply to clinical patients.”
As a sleep expert, Samuels says certain napping behaviours are “definitely concerning” and he looks at whether napping is pathological in a patient. However, he says this study failed to ask participants the type of questions that would help determine that.
Boulos agrees with the study in that it points out that regularly napping for long periods can be harmful to your overall health. He says you want to “emphasize good sleep at night” and not to take away from that by napping during the day unless it’s absolutely necessary.
Naps shouldn’t be longer than 30 minutes, experts say
When it comes to his recommendations, Samuels says a nap can be beneficial under the right circumstances. One of those reasons is to recover from sleep debt.
“We know that 30 percent of the North American population run around with a 10 to 15 hour of sleep debt per week, and that accumulates over time,” Samuels explains. “Napping in the context of not getting enough sleep, is very important in our view from a health perspective.”
When working with his patients like athletes who are travelling for sporting events, police officers, and night shift workers, he sets out a napping strategy for each one to recover from sleep debt regularly.
“The basic rule is that your naps should not exceed 30 minutes unless you're severely sleep deprived,” he says. “Usually we time the nap […] 12 hours from the midpoint of your nighttime sleep is actually the timing of the nap. So, you know if you go to bed at 11 and get up at six or seven, we're timing the nap for sort of 3 pm.”
Similarly, Sleep On It Canada, which is a sleep campaign launched by various Canadian sleep organizations, recommends keeping naps short and taking them in the early afternoon.
While napping can have its benefits, the sleep campaign lists several problems that can come from long naps, including cognitive issues, temporary grogginess, and the inability to sleep at night.
Boulos agrees power naps can be beneficial sometimes, but stresses that napping should be avoided when possible.
“Most of the literature is pointing towards napping for less than an hour, and ideally, you're still getting sufficient sleep at night. That's the ideal world but if you didn't get that, then maybe a power nap for less than an hour,” says Boulos, who is also a consultant sleep neurologist at Sunnybrook Health Sciences Centre in Toronto.
A 2020 European Society of Cardiology study found that napping for more than one hour does come with risks. Researchers found that naps longer than 60 minutes, were linked with a 34 percent higher risk of cardiovascular disease compared to no napping.
Naps under 60 minutes, were found as not risky for developing cardiovascular disease and the study found a short nap could actually “improve heart health in people who sleep insufficiently at night.”
Regularly taking long naps may mean you have a sleeping problem
Boulos and Samuels agree that people who need to take long naps during the day may have a sleeping problem and say those individuals should seek help.
“Our sleep health promotion is very poor in Canada,” Samuels explains. “There's no question that if people are struggling with their sleep, if they're shift workers, and they're struggling, they really should go to their primary care provider and ask for help because there are trained sleep physicians in the country.”
That’s why Samuels says the timing of a nap is so important because there are a host of negative consequences to oversleeping during the day.
If you need help finding sleep medicine health services, the Canadian Sleep Society has a map on its website that lists different sleep clinics.
Adults need 7 to 9 hours of sleep a night to function their best
According to the National Sleep Foundation, most adults need between seven to nine hours of sleep each night to “function their best during the day, and to keep their body and mind in optimal shape.”
The foundation lists a whole host of medical problems that can arise from a lack of sleep, including Alzheimer’s, cardiovascular disease, depression, and high blood pressure.
If you struggle to get proper sleep each night, there are recommendations to improve your sleep, like creating a relaxing evening ritual, sticking with consistent sleep patterns and a routine, and removing electronics from your bedroom.
If you still find you can’t get sufficient sleep at night, experts say rather than depending on naps, you should seek professional help to deal with the bigger issue.
“Overall, excessive napping is harmful for you,” Boulos says. “It should really be minimized as much as possible. You want to emphasize good sleep at night, and then you don't really want to sleep during the day unless absolutely necessary. That would be the takeaway message.”