An afternoon snooze may seem harmless, however, new research suggests drifting off for more than an hour may be bad for our health.
Around a third of Britons are said to battle insomnia. While a night of tossing and turning may leave you feeling fatigued and irritable the next day, long term sleep deprivation has been linked to obesity, diabetes and high blood pressure.
The benefits of naps have been debated, with studies previously linking too many daytime snoozes to heart disease.
To learn more, scientists from Guangzhou Medical University in China looked at over 313,000 people from 20 studies.
Results suggest napping for more than an hour is linked to a 30% higher risk of premature death and 34% greater odds of developing heart disease.
Napping for less than an hour, however, may boost heart health in those who struggle to sleep at night, added the scientists.
“If you want to take a siesta, our study indicates it’s safest to keep it under an hour,” said study author Dr Zhe Pan.
“For those of us not in the habit of a daytime slumber, there is no convincing evidence to start.”
According to the NHS, most adults need between six and nine hours of sleep a day.
A night staring at the ceiling may affect your focus the following morning, however, the odd bout of insomnia is not associated with lingering health concerns.
People who frequently struggle to nod off come nighttime may rely on an afternoon nap to get them through the day, with studies throwing up mixed results as to whether they are good for us.
“Daytime napping is common all over the world and is generally considered a healthy habit,” said Dr Pan.
“A common view is napping improves performance and counteracts the negative consequences of ‘sleep debt’.
“Our study challenges these widely held opinions.”
Out of the more than 313,000 participants, 39% napped.
The results, presented at the virtual European Society of Cardiology conference, suggest napping for more than an hour is linked to a greater risk of premature death and heart disease.
It is unclear how often the participants snoozed during the day, for example once a week or month.
“Our study did not focus mainly on the napping frequency and the majority of studies included did not report it,” Dr Pan told Yahoo UK.
“Further studies regarding the frequency are needed.”
Read more: Should offices have nap pods?
After taking into account the amount of shut eye the participants got during normal sleep hours, the scientists found long naps were only linked to an increased risk of premature death in those who nodded off for more than six hours at night.
Although unclear, napping has been linked to higher levels of inflammation, which may trigger heart disease.
The results further revealed, however, napping for less than an hour was not linked to any adverse health events.
“The results suggest shorter naps (especially those less than 30 to 45 minutes) might improve heart health in people who sleep insufficiently at night,” added Dr Pan.