- In a Chinese study, 40% of participants said they nap
- The researchers found that naps of any length were associated with a 19% increased risk of premature death
- They recommend that if people want a 'siesta', they should keep it under an hour
A frequent need to nap could be a red flag for future heart problems and a higher risk of early death, a new analysis concludes.
Long naps lasting more than an hour are associated with a 34% elevated risk of heart disease and a 30% greater risk of death, according to the combined results of 20 previous studies.
Overall, naps of any length were associated with a 19% increased risk of premature death, a Chinese research team found. The study results were released for presentation at the virtual annual meeting of the European Society of Cardiology.
'Keep it under an hour'
"If you want to take a siesta, our study indicates it's safest to keep it under an hour," lead researcher Zhe Pan of Guangzhou Medical University said in a society news release. "For those of us not in the habit of a daytime slumber, there is no convincing evidence to start."
For their study, the researchers analysed data from 20 studies involving more than 313 000 participants. About two in five people in the studies said they nap.
The investigators found that the connection was more pronounced in people aged 65 and older: These older folks had a 27% higher risk of death associated with napping and a 36% greater risk of heart disease. Women also had a stronger association between napping and poor health, with a 22% greater risk of death and a 31% greater risk of heart problems.
Interestingly, long naps were linked with an increased risk of death in people who sleep more than six hours a night. That would seem to rule out poor sleep as an explanation for the increased risk of death and heart health issues.
Adults who get less than seven hours of sleep each night are more likely to say they've had a heart attack, according to the US Centers for Disease Control and Prevention. Poor sleep also has been linked to high blood pressure, type 2 diabetes and obesity, all of which increase the risk of heart disease, heart attack and stroke.
Taking a 'power nap'
Pan speculated that long naps might affect the body because they are associated with higher levels of inflammation.
But heart health experts said that just because you're sleeping through the night doesn't mean you've had a good night's sleep – something for which this study doesn't account.
Regarding how well you're resting at night, napping "might be a sign that there's something else going on," said Dr Nieca Goldberg, a cardiologist and director of the NYU Langone Center for Women's Health, in New York City.
"What kind of sleep were these individuals getting?" Goldberg said of the study participants. "Were they waking up at night? Did they have sleep apnoea?"
Dr Matthew Tomey, a cardiologist with Mount Sinai Morningside in New York City, agreed that these people might be suffering from poor sleep.
"Some people take naps as a matter of habit, or they take a power nap," Tomey said. "For others, they're taking potentially longer naps during the daytime because of too little or too poor quality sleep at night."
People should take a nap when they feel like it, but if they regularly need naps that could be a sign of trouble, Tomey said.
Good sleep habits
"If they notice that they feel excessively sleepy during the daytime, needing multiple or long naps, that's a wake-up call to pay attention to the quality and quantity of their nighttime sleep," he added.
People who frequently nap should talk with their doctor about their sleep issues, since they might be suffering from sleep apnoea or some other issue that disrupts quality sleep, Tomey and Goldberg said.
Good sleep habits, according to the CDC, include:
- Sticking to a regular sleep schedule
- Getting enough natural light during the day, to positively influence brain chemicals related to sleep
- Exercising regularly, but not within a few hours of bedtime
- Avoiding artificial light near bedtime
- Keeping your bedroom cool, dark and quiet
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