Scientists at the University of California, Berkeley, have uncovered a potential mechanism in humans that explains how and why brain waves during deep sleep at night are able to regulate the body’s sensitivity to insulin, which in turn improves blood sugar control the next day as researchers link lack of sleep to an increased risk of developing diabetes without knowing the exact cause.
“These synchronized brain waves act like a finger knocking over the first domino to start a linked chain reaction from the brain, all the way to the heart and out to change the body’s regulation of blood sugar,” said Matthew Walker, a professor of neuroscience and psychology at UC Berkeley and senior author of the new study, reports Al-Rai daily.
“In particular, the combination of two brain waves, called sleep spindles and slow waves, predicts an increase in the body’s sensitivity to the hormone insulin, which in turn beneficially lowers blood glucose levels,” Walker added.
The researchers say this is an exciting advance because sleep is a modifiable lifestyle factor that can now be used as part of an adjunctive and painless treatment for those with high blood sugar or Type 2 diabetes.
The same team of UC Berkeley researchers previously found that brain waves during deep sleep improve the ability of the hippocampus (the part of the brain associated with learning) to retain information.
The researchers first examined sleep data in a group of 600 people, and found that this particular set of brain waves during deep sleep predicted glucose control the next day, even after controlling for other factors such as age, gender, and sleep duration and quality.
Next, the team set out to explore the downward pathway that might explain the relationship between brain waves during deep sleep sending a signal to the body and ultimately predicting blood glucose regulation.
First, they found that stronger coupling of brain waves during deep sleep predicted a shift in the state of the body’s nervous system to a quieter branch, called the parasympathetic nervous system. And they measured this change in the body’s transition to this reduced stress state using heart rate variability as a proxy.
The researchers also discovered that switching deep sleep to the calming branch of the nervous system also predicted an increase in the body’s sensitivity to the hormone insulin, which instructs cells to absorb glucose from the bloodstream, preventing a “harmful” rise in blood sugar.
“As you sleep at night, a series of electrical brain waves occur that send a reset and calm down of the nervous system for the next day,” Walker said.