With Memorial Day kicking off summer here in Michigan, we’re already looking for ways to keep cool. Many of us envision this: 
However, having grown up with a sun-sensitive redheaded mom, I know the drill: lightweight long-sleeved shirts and pants, brimmed hat, avoid the sun, and drink hot tea.
Later in life, an archaeologist friend reinforced the mantra, advising his crew to eschew cold, icy beverages when working in the hot sun and to drink room temp or warm beverages instead.
While this may sound counterintuitive, envision desert dwellers. Not in current-day Phoenix, but in traditional desert societies, where hot beverages are consumed year round.
Well, okay, until pretty recently in human history, desert regions didn’t have a supply of ice at hand, making the whole issue rather moot.
But still, as Yasmin Noone (2018) points out, even today Moroccans drink hot mint tea year-round and
hot tea is . . . commonly drunk in warm conditions throughout India, Malaysia, Turkey, Egypt, United Arab Emirates, Saudi Arabia and South Africa.
A 2012 study indicated that when you drink hot beverages, you sweat more, so “under conditions permitting full sweat evaporation,” your body cools down as the energy (heat) trapped in the sweat is absorbed by the air (Bain et al.). The researchers surmised that sensors—like those in your mouth, esophagus, and stomach—detect the heat, triggering the sweating reaction.
But note the “full sweat evaporation” part. If the sweat is trapped by heavy or tight clothing, full evaporation won’t take place.
In addition, the color of your clothing may make a difference. According to Inglis-Arkell (2012), black attire is the best:
Black absorbs everything coming in from the sun . . . [and] absorbs energy from the body instead of reflecting it back. . . . Once it has absorbed heat, it has to have some way to radiate it away. If there’s even a little wind, black clothing is the better choice [over white] for those who want to keep cool.
Again, it works only with evaporation, so your black clothing must be loose enough to allow that to happen.
Drinking hot beverages isn’t the only way to activate sweating.
Chili peppers work on the same thermal sensors as that hot tea does, giving you the same end result. (Would it work with double efficiency if you combine temperature and spicy heat by quaffing a warm cup of Chili Chocolate tea!?)
However, as you sweat, fluids are lost, so keeping hydrated is critical.
Soooo, if you eat spicy food and drink hot tea simultaneously, will you feel especially cooler but get dehydrated more quickly?? Does the fluid intake of the tea offset the sweating??
And does this drink hot liquid to cool down theory even hold up? There’s a lot of discussion about this, with many arguing that this really isn’t true. A hot drink does, after all, add at least a little warmth to your body.
When Smithsonian.com (2012) interviewed Ollie Jay, one of the researchers in the 2012 study, he said that if that sweat isn’t going to evaporate—like on a very humid day or if you’re wearing too many clothes—you’re better off drinking a cool beverage.
So after you’ve quaffed that hot tea, perhaps an iced tea chaser is in order! You know, just to be sure!
Sources:
–Bain, A. R., N. C. Lesperance, and O. Jay, “Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation,” Acta Physiological 206(2):98–108, 5/10/12.
–Inglis-Arkell, E., “The physics that explain why you should wear black this summer,” io9 Gizmodo, 4/23/12.
–Noone, Yasmin, “Why you should drink hot tea and eat chillies in summer to cool down,” SBS, 12/12/18.
–Stromberg, J., “A hot drink on a hot day can cool you down,” Smithsonian.com, 7/10/12.
It's More Than Tea 