Turns out that a particular kind of deep sleep — called slow-wave sleep (SWS) — may be essential to maintaining balanced blood sugar.
When folks in a study were intentionally deprived of the deepest stages of SWS, they suffered a 25 percent drop in insulin sensitivity — a marker of the body’s ability to convert blood sugar into energy.
The light sleeping also caused a 23 percent drop in glucose tolerance, another risk factor for diabetes.
So even if you get a proper 8 hours of sleep, it may not be doing your blood sugar any favors if you’ re not sleeping soundly.