Feeling Sleepy, Napping Too Long May Signal Diabetes Risk

Tired businesswoman in office

Sleep deprivation seems to have become the norm for many in the modern world. The bright screens of tablets and smartphones in particular tend to lure users to stay up later than expected. But all that missed sleep can catch up with you the following day in the form of drifting off during a meeting or dozing while you wait for the bus. While that may not seem like a big deal, it may signal trouble for those who make a habit out of it. New research published this week has found that feeling too sleepy during the day or taking long naps may signal a risk for diabetes.

Why is sleep important?

Sleep is an often-neglected aspect of life, but it’s an essential player in keeping our minds and bodies healthy. Exactly why humans need sleep, how much, and in what forms is still an area of intense research.

In spite of that, sleep researchers have found sleep to play a role in a variety of aspects of health. Perhaps the best known is the essential function of sleep in storing and ordering memories in the brain. Many studies have found that people who are sleep deprived have trouble learning new information and storing it for remembering later. Other studies have found that sleep seems to help clear waste out of the brain after a long day of activity, but how exactly that happens still isn’t well understood. Sleep is also critical to overall physical health. Many studies have shown that lack of sleep affects the immune system, slowing down the healing process and making sleep-deprived individuals more likely to get sick.

Why do we worry when sleep gets thrown off?

Sleep can get interrupted for many reasons including anything from a screaming baby to a room that’s a little too hot. Most of the time, sleep troubles are the result of bad habits around bedtime. Staring at bright screens or using your bed for more than just sleeping can send the wrong signal to your brain and make it hard to drift off at the right time.

But changes in sleep patterns can also be a hallmark of disease. Depression is well known to cause dramatic changes in sleep, sometimes making it hard for a person with depression to fall asleep or stay asleep. Older adults with dementia and Alzheimer’s disease also often experience changes or even complete reversals in their sleep cycle. Doctors worry when there’s a change in the sleep cycle or when people feel sleepy even after a long night of sleep because it indicates something more might be going on. This study wanted to see if diabetes might be added to that list of diseases to think about in patients with sleep troubles.

How did the researchers link sleep to diabetes?

The team looked for studies done in the past that had examined napping and daytime sleepiness. In total, that represented 10 different studies that covered more than 265,000 participants in countries that included Spain, Germany, China, Sweden, Finland, and the USA. They pooled the data from all of those studies into a single bin and then reanalyzed the data on all of these people who either napped during the day or felt excessively sleepy to see if they were more likely to have other health issues. This kind of study is called a meta-analysis. The team found that people who napped for more than an hour during the day were at significantly higher risk of having diabetes. The same was true for those who felt excessively tired during the day. Interestingly, napping for less than 40 minutes didn’t carry a diabetes risk.

Why would sleep be related to diabetes?

The researchers think sleep apnea may be contributing to this picture. Sleep apnea is a disease that blocks breathing during sleep and causes a person to wake up many times each night. These people often feel tired throughout the day and may nap to make up for their lack of sleep. The condition has been shown to increase your risk for high blood pressure, stroke, liver problems, and diabetes. Unrelated to sleep apnea, the team also thinks the relationship might work in the opposite direction, where people who are generally in worse health also tend to feel more tired and feel the need to sleep more. Finally, depression is also linked with sleep problems and with diabetes and may be acting as a common link between the two.

What does this mean for me?

This study reinforces how important sleep is to health both when you’re recovering from illness and when you’re trying to prevent it. If you find yourself having to nap for long periods of time during the day to feel rested or are constantly tired even after a long night of sleep, you should see a doctor to figure out what’s going on. The sleep troubles could signal an underlying medical condition and fixing it may save you from more trouble further down the line.