D: Yaël, if you were traveling through a desert and you happened upon an oasis where a fellow traveler had only a cup of hot tea to offer you, would accept it or say, “No way”?

Y: Don, of course I would accept. In that situation, it’s critical to stay hydrated. Plus, hot tea on a hot day has the potential to significantly cool me down.

D: True, it’s more than a bit of traditional wisdom: under the right circumstances, a hot beverage on a hot day can be your most effective means of regulating body temperature. When you sip the hot drink, it’s warmer than your body and causes your temperature to rise. This increases perspiration to counteract the added heat.

Y: The receptors in your mouth and throat that send signals to your brain when you drink something hot are the same ones that respond to chemicals in chili peppers. So, perhaps it’s not surprising that drinking hot drinks to cool down is a popular practice in countries where spicy chilies are a staple of cuisine.

D: Sweating can offset the relatively small amount of heat contained in a hot drink or a spicy dish. But to do so, the sweat must evaporate. When the sweat evaporates, its energy as stored heat is removed from the body. But if you wipe the sweat away or it drops to the ground, it doesn’t evaporate. So, the energy remains in the body, and you stay hot.

Y: Proportion is key, here. The heat from a relatively small hot tea produces a disproportionate amount of sweat that cools the body more effectively than room- temperature water.