Deep sleep brain waves can predict next-day blood sugar levels

A team of researchers, including one of Indian-origin, has uncovered a potential mechanism in humans that explains how and why deep-sleep brain waves at night are able to regulate the body's sensitivity to insulin, which, in turn, improves blood sugar control the next day.

Researchers have known that a lack of quality sleep can increase a person's risk of diabetes. What has remained a mystery, however, is why.

Now, new findings from a team of sleep scientists at the University of California, Berkeley, are closer to an answer.

"Synchronised 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," said Matthew Walker, a UC Berkeley professor of neuroscience and psychology and senior author of the new study.

In particular, the combination of two brain waves, called sleep spindles and slow waves, predict an increase in the body's sensitivity to insulin, which beneficially lowers blood glucose levels, Walker explained in the study published in the journal Cell Reports Medicine.

The researchers say this is an exciting advance because sleep is a modifiable lifestyle factor that could now be used as part of a therapeutic and painless adjunct treatment for those with high blood sugar or Type 2 diabetes.

"The results also show that these deep-sleep brain waves could be used as a sensitive marker of someone's next-day blood sugar levels, more so than traditional sleep metrics," said Vyoma D. Shah, a researcher at Walker's Center for Human Sleep Science and co-author of the study.

The findings also suggest a novel, non-invasive tool -- deep-sleep brain waves -- for mapping and predicting someone's blood sugar control.

The researchers first examined sleep data in a group of 600 individuals. They found that this particular coupled set of deep-sleep brain waves predicted next-day glucose control, even after controlling for other factors such as age, gender and the duration and quality of sleep.

"This particular coupling of deep-sleep brain waves was more predictive of glucose than an individual's sleep duration or sleep efficiency," said Raphael Vallat, a UC Berkeley postdoctoral fellow.

The researchers subsequently replicated the same effects by examining a separate group of 1,900 participants.

The scientists said the research is particularly exciting given the potential clinical significance years down the line.

The prospect of new technologies that can safely alter brain waves during deep sleep, that this research has uncovered, may help people better manage their blood sugar, the researchers noted.