Dear Living Well Daily Reader,
Have you ever woken up from a long afternoon nap and found yourself confused, grumpy and feeling even more exhausted than you did before your slumber? But you wake from short naps feeling refreshed and recharged?
There’s a good reason for this.
It’s called sleep inertia. We will reveal how it (and another common sleep issue) might be ruining your health in just a bit.
And according to some groundbreaking new research, being grumpy and groggy should be the least of your worries if you’re indulging in lengthy daytime naps.
You see, this habit can increase your chances of developing a debilitating and often deadly condition by a whopping 45 percent.
After studying the health data of more than 300,000 people, a team of researchers from the University of Tokyo finds that folk who enjoy a daytime snooze longer than one hour each day are 45 percent more likely to develop Type 2 diabetes.
While it’s still unclear whether extended daytime sleeps are a symptom or cause of this dangerous disease, one thing is certain — the link totally disappears with when naps are less than 40 minutes.
Dr. Yamada Tomahide, lead researcher for the analysis, reports that one reason for this is “A short nap finishes before the onset of deep slow-wave sleep. Entering deep slow-wave sleep and then failing to complete the normal sleep cycle can result in a phenomenon known as sleep inertia, in which a person feels groggy, disoriented and even sleepier than before napping.”
In addition, Tomahide and the team hypothesize that shorter naps may help reset abnormal sleep cycles and help improve a host of abnormal body functions caused by sleep deprivation.
Sleep deprivation is linked to many health issues including increased stress hormone secretion, inflammation, increased appetite and improper carbohydrate metabolism.
Because of these factors, the scientists believe the findings could also be a “reverse causality,” meaning that folks who take long daytime naps could likely be more ill and experience other risk factors for diabetes.
Clinical trials will be needed to determine the exact cause of the link.
Professor of metabolic medicine at the University of Glasgow Naveed Sattar reports:
This observational study shows an association between longer naps and diabetes. It’s likely that risk factors which lead to diabetes also cause napping… That said, there is now abundant evidence of a link of sorts between sleep disturbances and diabetes. What we need are trials to determine if… how long one sleeps makes a difference to real health outcomes.
In the meantime, try to keep your daytime snoozes under 40 minutes.
Managing editor, Living Well Daily