A brief catnap may help boost your energy and alertness later in the day, but people who take long daily sleep siestas put themselves at higher risk for diabetes, according to new research.
In a new study publicized by the LiveScience Website, sleep specialists from the Leiden University Medical Center in the Netherlands who studied 27,000 Chinese men and women found those who napped more than hour a day were far more likely to suffer the metabolic disorder.
The research, published in the journal Sleep Medicine, determined that naps have different effects on the body, depending on sleep duration. The results showed longer naps were associated with an increased risk for high blood sugar and diabetes, while brief burst of shut-eye — lasting 30 minutes or less — lower blood-sugar levels.
"The findings may have important implications for people who regularly nap," said Eliane Lucassen, a Leiden researcher. "Taking a so-called power nap may be useful for certain individuals, but naps should not be too long."
Past studies have shown a short afternoon sleep can boost cognitive function, but a lengthy sleep session during the day can lead to chronic insomnia and other problems.
The new study examined the sleep habits of 27,000 Chinese retirees, most of whom regularly took afternoon naps. Researchers divided them into four groups based on their nap duration, ranging from zero minutes to more than 60 minutes. The results showed that those who reported napping for more than an hour each day had a higher risk of pre-diabetes and diabetes compared to those who never nap.
Researchers noted previous studies have suggested diabetes may be caused by getting too little, or too much, nighttime sleep. As a result, people who take longer naps may sleep less at night, boosting their diabetes risk, Lucassen said. It's also possible napping may disturb the body's internal clock that regulates the 24-hour cycle and affect release of insulin.