Sleep and Diabetes: Scientists Explain the Link

Researchers have uncovered a mechanism that may explain why a lack of quality sleep can increase the risk of diabetes.

Previous studies have found that sleep problems, such as repeated awakenings during the night or insufficient sleep, promote glucose intolerance and can play a role in how sleep and type 2 diabetes are linked. The reasons why are not well understood, but a new study published in the journal Cell Reports Medicine may offer an explanation.

A group of sleep scientists at the University of California, Berkeley, examined sleep data of 647 people. They found that a combination of two deep-sleep brain waves, called sleep spindles and slow waves, can predict next-day glucose control better than an individual's sleep duration or efficiency.

"These synchronized brain waves act like a finger that flicks the first domino to start an associated chain reaction from the brain, down to the heart, and then out to alter the body's regulation of blood sugar," says Matthew Walker, a UC Berkeley professor of neuroscience and psychology and senior author of the new study.

The findings suggest that stronger and more frequent coupling of the deep-sleep brain waves predict a switch in the body's nervous system state into the more calming branch, called the parasympathetic nervous system. This further predicts an increased sensitivity of the body to the glucose-regulating hormone called insulin.

"In the electrical static of sleep at night, there is a series of connected associations, such that deep-sleep brain waves telegraph a recalibration and calming of your nervous system the following day," Walker adds. "This rather marvelous associated soothing effect on your nervous system is then associated with a reboot of your body's sensitivity to insulin, resulting in a more effective control of blood sugar the next day."

The researchers replicated the same effects by examining a separate group of 1,900 participants and now hope other research groups will yield the same results.

Diabetes affects over 37 million people, or 11.3% of the United States population, and the rates are expected to rise. An additional 20% of the U.S. adults deemed medically "healthy" may have a pre-diabetic glucose metabolism pattern, a recent study found.

Type 2 diabetes is the most common form of the disease and occurs when the body doesn't produce enough insulin or the body's cells don't react to insulin. The condition has no cure but can be managed with medications, physical activity, a low-sugar diet, and quality sleep, according to the Centers for Disease Control and Prevention.

Earlier research has suggested that people with short sleep durations are about 40% more likely to develop diabetes than those who sleep seven to eight hours. Moreover, the increased risk for diabetes due to sleep disturbances is similar to that of having a family history of type 2 diabetes.

Although sufficient sleep won't cure type 2 diabetes, the study authors hope the findings could be used to develop new technologies to safely alter brain waves during deep sleep to help patients better manage their blood sugar.