When we feel the urge to yawn in cooler weather, we should succumb—it might do us good. New research suggests that beyond signaling fatigue or boredom, yawning might be a physical reaction to cool an “overheated” brain.

A study at Princeton University is the first to show that the frequency of yawning varies with the season and that people are less likely to yawn when the heat outdoors exceeds body temperature. The research monitored 160 people, 80 per season, during winter and summer in Tucson, Arizona. According to the researchers’ theory, it is possible that yawning in cooler temperatures works to cool the brain, while yawning in warmer conditions appears to provide no similar relief.

Research associate Andrew Gallup remarks, “The applications of this research are intriguing… for better understanding diseases and conditions such as multiple sclerosis or epilepsy, which are accompanied by frequent yawning and thermoregulatory dysfunction.” Excessive yawning may prove a helpful diagnostic tool.