Getting a good night's sleep is essential for health, especially for diabetes patients. Studies have shown that poor sleep increases the risk of diabetes, but the exact mechanism by which sleep controls blood sugar levels was not known. In a new study, researchers from the University of California have unraveled the mystery.

The research team discovered how deep-sleep brain waves at night regulate a person's insulin sensitivity, which determines blood sugar control the next day. According to them, the coupling of deep-sleep brain waves, called sleep spindles, and slow waves is responsible for predicting insulin sensitivity.

"In an examination of over 600 humans, we demonstrate that the coupling of non-rapid eye movement (NREM) sleep spindles and slow oscillations the night before is associated with improved next-day peripheral glucose control," the researchers wrote.

"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. In particular, the combination of two brain waves, called sleep spindles and slow waves, predict an increase in the body's sensitivity to the hormone called insulin, which consequentially and beneficially lowers blood glucose levels," Matthew Walker, a senior author of the study, said.

The study, published in Cell Reports Medicine, suggests sleep quality is more important than quantity for diabetes patients, and sleep modification may be an effective lifestyle change that can help in controlling blood sugar levels.

Researchers believe the findings could help in using sleep as a therapeutic and painless adjunct treatment for people with diabetes.

"Beyond revealing a new mechanism, our 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 co-author of the study.

"Adding to the therapeutic relevance of this new discovery, the findings also suggest a novel, non-invasive tool — deep-sleep brain waves — for mapping and predicting someone's blood sugar control," Shah added.