How A Hot Beverage Actually Cools Down Your Body (Yes, It's True)

When you find yourself out and about on a day that feels like it's scorchingly hot enough to fry an egg on the sidewalk, nothing sounds less appealing than a steaming mug of, well, anything. A hot beverage simply doesn't catch the eye in the same way that a chilled glass of water does. But, as it turns out, this decision might be just backwards. While an ice-cold beverage may appeal to us, drinking something warm on a hot day can actually be more effective in cooling our bodies.

As counterintuitive as it seems, when you drink something warm, receptors in your mouth and throat indicate an increase in temperature, which causes your body to perspire. Perspiration is, of course, how your body copes with heat, releasing sweat all over your skin to cool you down via evaporation. It is something that our bodies do naturally when we are hot, so it makes sense that sweating more would help to cool us down. Although ingesting warm liquid will slightly increase your core temperature, this doesn't undo the effects of perspiration as a scientific study has shown that evaporative cooling will still be effective — that is, so long as you find yourself under the right conditions.

Evaporative cooling is an effective means of lowering temperature. As liquid water transforms into vapor, it sucks up thermal energy, cooling the surrounding area. This process is why our bodies sweat or why dogs pant when they're hot. It's also the science used in some air conditioning units. That said, the effectiveness of this process depends largely on humidity.

Humidity accounts for the amount of water vapor that can be held in the air. For example, 80% humidity means that the air is holding 80% of the maximum quantity of vapor for a given temperature. As you might expect, lower levels of humidity mean air will easily and quickly take on more water vapor, which allows for more effective evaporative cooling. This is why you might feel like your clothes soak with sweat that never dries on a hot and humid day, whereas you might not even notice that you're sweating on a scorching day in the desert. 

So, while enjoying a steaming mug of coffee in the still and humid heat of a bayou is unlikely to make you feel much better, if you find yourself sitting among the saguaros of the Lower Sonoran, that hot drink might be just what you need — especially if there's a little breeze to enhance the evaporation. However, none of this should be a surprise as people living in hot and low-humid climates have been cooling down with warm beverages for ages.

If you consider all of the unique hot drinks from around the world, you'll see that many of the beverages originate from places that are quite warm. While the scientific reason for cooling down with a hot beverage may have been unknown, many people living in these climates have often enjoyed steamy drinks for relief — just look at the consumption of mint tea in North Africa, coffee in the Middle East, or even chai in India.

Interestingly, this phenomenon extends beyond hot drinks to include spicy foods. If you've ever wondered how someone in the jungles of Thailand could possibly enjoy a steaming bowl of spicy tom yam pla, the same receptors in your mouth that judge temperature are also triggered by capsaicin, the chemical that makes foods taste spicy. This is why fiery foods sometimes cause you to break out in a sweat. Some even think that the cooling effects of spicy dishes may even be why chilies tend to be so popular in hotter parts of the world.

In the end, hot drinks might not effectively hydrate you like Gatorade, particularly after heavy activity. But, if you are looking for a drink to cool you down — and the weather conditions are right — you might want to try sipping something hot.