By Perry Luckett

For much of my seven decades on the planet I’ve believed the seemingly odd concept that I could cool myself down, even during hot weather, by drinking hot coffee or tea. That probably stems from my German mother and grandmother, who both practiced this technique in my home state of Wisconsin. I honored my forebears whenever I could, but I still didn’t turn down a tall glass of Kool-Aid or a bottle of Hams beer when offered in the summer—even though their cooling effect lasted only a few minutes.

Hey, you can’t argue with science, right?

A recent article by Zac Cadwalader at Spruge.com appears to confirm my mother and grandmother’s practice. Zac is a hot-coffee zealot, insisting “I’ll drink hot coffee while standing next to an open flame, cooking burgers, during 100°+ (F or C, I don’t care) Texas summers. But if keeping cool is your end game, according to Science, then you shouldn’t be switching from hot coffee.” He goes on to cite the science behind this belief, as reported by University of Cambridge neuroscientist Peter McNaughton (from Deutsche Welle.com):

Drinking hot beverages increases your core temperature, which then cues the body’s natural response to increase perspiration. Nerves in your mouth and upper digestive tract respond to the heat of the beverage, stimulating your brain to produce more sweat. As the sweat evaporates from your skin, it acts as a coolant that more than compensates for the heat a hot beverage adds to your body. Cool huh?

This cooling effect also is stronger and longer lasting than just drinking a cold beverage. Professor McNaughton adds: “Cool drinks only cool you momentarily because the volume of the cold drink is relatively small when compared to your body, so the cooling effect gets diluted quite quickly.” The more cold drinks you consume, the more your blood vessels tighten, making you feel much hotter.

As usual, though, there’s a hitch

And its name is humidity. Turns out “cooling by heating” works only if all the sweat produced by drinking your hot beverage can evaporate. As Wisconsin summers wore into July and August, I found myself drinking more Kool-Aid and less hot coffee or tea. Later, when I worked outside on construction or roofing crews during summers in Florida, I abandoned hot drinks altogether—first because my fellow construction workers would have thought I’d gone nuts if I reached for a thermos and then because my instinct for survival was stronger than my loyalty to the ideas of my materfamilias. On the other hand, hot coffee or tea works just fine during the typically hot, dry days of Colorado’s semi-arid summers.

Does science also explain this caveat? Yes, according to Ollie Jay, researcher at University of Ottawa’s School of Human Kinetics. As he told Joseph Stromberg for a 2012 article at Smithsonian.com, “On a very hot and humid day, if you’re wearing a lot of clothing, or if you’re having so much sweat that it starts to drip on the ground and doesn’t evaporate from the skin’s surface, then drinking a hot drink is a bad thing. 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.”

So, summing up . . .

If you’re reading this on the East Coast, in the Midwest, or in the sweaty Deep South, keep those cold drinks coming! But if you’re in Utah, Colorado, New Mexico, or northern Arizona, brew up some hot tea or coffee and enjoy the cooling effects of cozy hot beverages. (Pay no attention to those stares from others—you’re a maverick, after all.) What if you’re in southern Arizona—say in Tucson or Phoenix? Go North for goodness sake! Humans aren’t meant to live in 120-degree heat, no matter how dry it is. Gila monsters maybe, humans no.

Have an opinion about hot or cold drinks for summer cooling? Let us know in the Comments section below . . . and stay thirsty, my friends.

Sources:

Joseph Stromberg, Smithsonian.com, July 10, 2012. https://www.smithsonianmag.com/science-nature/a-hot-drink-on-a-hot-day-can-cool-you-down-1338875/#lkA1uK17sW73zO9x.99

Julie R. Thomson, This Is Why a Hot Drink Will Actually Cool You Down. Huffington Post, Food and Drink, June 2, 2017. https://www.huffingtonpost.com/entry/hot-drink-cools-you-down_us_592f6757e4b0540ffc84583e

Lindsey Goodwin, Can Hot Drinks Cool You Down? The Science Behind the Claim, September 19, 2017.  https://www.thespruceeats.com/can-hot-drinks-cool-you-down-765049

Zac Cadwalader, Hot Coffee Does a Better Job of Cooling You Down than Cold Drinks Do, May 7, 2018. Sprudge.com

Deutsche Welle.com, Science, http://www.dw.com/en/does-drinking-hot-drinks-on-a-scorching-summers-day-really-cool-you-down/a-16974502