I prefer my coffee hot versus iced, even in the summer. Inevitably, this means whichever friend I’m with at the coffeeshop will stare at me quizzically while slurping her 70-ounce cold brew. I’ve heard that hot beverages cool the body down, so I’d sometimes deploy that as a smug, “see, I know what I’m doing” excuse. But really, I didn’t understand why that would be the case. Something to do with sweating? Or blood pressure? Science, help a girl out! Eager to get to the bottom of it, I contacted experts to find out whether it’s true that hot beverages cool the body down.
Turns out, the science supporting this claim is dicey. I contacted numerous health-care experts from prestigious institutions like the Cleveland Clinic. They didn’t have answers for me. A spokesperson for the Academy Of Nutrition And Dietetics told me she was “having trouble finding substantial research” to verify the assertion that hot beverages can help you cool off.
Finally, a decisive answer came from Douglas Casa, a professor at University Of Connecticut, a researcher at the Human Performance Laboratory, and an expert in thermoregulation. He tells me the claim that hot beverages cool the body down is—not his exact words—total bullshit.
“That is a very inaccurate old wives tale,” he told me. “Drinking warm beverages will warm up your body temperature. Conversely, drinking cold beverages will help to cool you down, which is very valuable during intense exercise in the heat.”
He points me to this meta-analysis of studies on beverage temperature, body temperature, and physical exertion, which points to decreases in bodies’ core temperatures when consuming cool versus warmer beverages.
A small wrinkle: A Smithsonian Magazine article I found indicates that drinking a hot beverage could cool you down if it makes you hot enough to sweat—and if you’re in a not-too-humid environment, and you’re wearing breathable clothing that allows this sweat to evaporate. (Seems to me like you’d have to get pretty sweaty for this to work. Gross.) The Smithsonian piece is based on the claims from one study conducted by a University Of Ottawa researcher in 2012. He didn’t respond when I contacted him to follow up on his study.
Even if that research is valid, it seems like a person would have to get really hot and sweaty in order for the warm beverage to cool the body down via perspiration. (Or you could just go run around the block a few times to achieve perspiration?) Bedraggled sweat rat is not exactly the look I’m going for at the coffeeshop, however, so I think I’ve been convinced to switch to iced lattes this summer. They taste more refreshing, to boot.