It all has to do with sweat.

Drinking a hot drink increases the body’s heat load and the body responds to that by sweating. The output of sweat is greater than the internal heat gain, and this is where it all starts to make sense ― when the sweat evaporates from the skin, it cools us down.

The sweat increases heat loss and reduces body heat storage. Good info to know, and it’s all thanks to Ollie Jay ― a researcher at University of Ottawa’s School of Human Kinetic ― and the research he published in 2012.

Our bodies sweat when we drink something hot because of nerve receptors on our tongue. When our tongue receives the information that a hot beverage is being consumed, it sends that info along to the brain, which then sets about to cool down the body by sweating.

But, there’s a little caveat you should know about. If you’re drinking a hot drink in an environment where the sweat won’t evaporate ― like somewhere hot and humid ― that hot drink probably won’t do the trick. You might want to stick to a cold beverage if that’s the case.

“The hot drink still does add a little heat to the body, so if the sweat’s not going to assist in evaporation, go for a cold drink,” Jay told Smithsonian.com.

We recommend iced coffee, of course.