When you’re snoring or having moments of decreased airflow, referred to as apneas, you’re more likely to rouse during the night, which can result in less time spent in the deep, restorative stage called rapid eye movement (REM) sleep and more time in light stages of sleep, says Raj Dasgupta, MD, a fellow of the American Academy of Sleep Medicine and assistant professor of clinical medicine at the Keck School of Medicine at the University of Southern California in Los Angeles. Beyond the restorative benefits it offers, REM sleep is when brain activity and calorie burn are at their highest, he explains. Your body utilizes a lot of glucose and energy and also dreams during REM sleep.
A 150-pound person who’s sleeping appropriately could burn around 50 to 60 calories a night, mainly in REM sleep, Dr. Dasgupta notes. But as he puts it, “If we’re having sleep-disordered breathing, it can make it hard for us to stay in REM sleep.” That means fewer calories burned.
Your hunger hormones wind up out of whack.
Disrupted sleep can alter the levels of two hormones related to weight regulation, explains Dr. Dasgupta. The first is leptin, a hormone that helps us feel satiated; the other is ghrelin, a hormone that makes us feel hungry. We secrete leptin in deep stages of sleep, and our bodies make more ghrelin when we’re sleep deprived. So if arousals from snoring keep us from reaching deep sleep and we’re not getting the quality shut-eye we need, we can wind up crazy hungry the next day (thanks, in part, to high levels of ghrelin encouraging us to snack more).