‘Hot’ is too broad a search term for the engine on here, so if it’s been asked before, I apologize.
I got a coffee today at the Tim Horton’s, despite the fact that it’s 40c/ 104F degrees outside. It is an indispensable…ahem…digestive aid that I don’t like to do without after lunch.
There were a couple of army guys who ordered in front of me, and one of them was complaining that he ordered a hot coffee instead of an iced coffee, wondering what was wrong with him.
“The Hot coffee’s better for you,” one his buddies told him. “The hot liquid better regulates your body heat, and so it makes you feel cooler.”
“That’s bullshit,” another soldier replied. “It’s because the hot liquid keeps you better hydrated, so you can tolerate the heat better.”
Now, both of these arguments stand up to my featherweight scrutiny. Therefore, I ask the dopers on here:
Is there any truth to hot liquids keeping you cool (or perhaps more simply, “comfortable”) in the heat?
it’s close to 40 where I am and I drink hot mint tea during the day. makes me sweat like crazy, then after 5 minutes or so the overall effect is cooling. also use a lot of hot peppers to the same effect.
i think the above is a tried and true method used in the desert and hot arabian countries.
If you drink something hotter than your body temperature, your body will have more net heat to dissipate. And the hotter the environment you’re in, the more time it will take to dissipate that heat.
Now, some will argue that their own body’s cooling mechanism will kick into overdrive only if they ingest hotter stuff. However, little research bears that out (google malignant hyperthermia, or heat stroke if you’re interested) and besides, each individual’s threshold for breaking out into a sweat is different, depending on temperature, physical activity, relative humidity, clothing worn, etc.
In short: If you’re hot and you want to cool off and an air-conditioned room is not an option, drinking beverages significantly below your body temperature is a good way to do so. Also cut back on exertion and get into the shade, and take advantage of any breezes blowing by.
IAMNot a doctor, and I don’t want to disagree with our esteemed Qadgop, but the following is what I learned about drinks in the summer:
Arabs and other desert-dwellers have drunk hot tea for centuries because only cooked water was sanitary (other places, like Ancient Greece, used diluted alcohol for the same reason) and because cooling was not practically possible for nomads. (Apparently, the Egyptians used porous clay pots that kept water cool by evaporation, since the Nile river was close enough).
A luke-warm tea - as opposed to boiling hot - will refresh you better than an ice-cold drink, because with an ice-cold drink, your body will expend energy to bring it up to body temp, which could increase your basic metabolism. By contrast, a luke-warm drink is very close to your body temp., so it replenishes your water without additonal exertion.
About a third of people are cold-sensitve and get “ice-cream headaches” after eating cold stuff. For them, a cold drink is not a good idea.
Also, many (older?) people anecdotally have stomachs sensitive to cold stuff, so for them, too, cold drinks are not good (being used or not to drinking cold drinks seems to play a role in this).
Staying in the shade, doing things slowly and drinking enough are of course generally very good tips to not overheat.
Hot drinks won’t help as much as cold drinks on a hot day, but any kind of mostly-water (anything but strong booze) drink will help, and the difference isn’t all that big. Ultimately, the cooling effect from drinking water depends on the heat of vaporization of water (the heat energy expended to evaporate the sweat that the water will become) and on the specific heat of water (the heat energy needed to raise or lower the temperature of the liquid to body temperature). The heat of vaporization of water is about 540 calories/gram, while the specific heat of water is 1 calorie/gram/degree C, so even the full range from freezing to boiling is less than 20% of the heat change from the evaporation. Thus, for instance, a drink that’s at freezing will dissipate 577 calories per gram (540 from evaporation, and 37 from going from freezing-cold to body temperature), while a drink that’s at boiling (if such a thing could be drunk safely) would still dissipate 477 calories per gram (540 from evaporation minus 63 from going from boiling-hot to body temperature).
Things change if you’re talking about iced drinks and you actually consume the ice (as opposed to letting it melt in the glass), because then you’re also dealing with the 80 calories/gram heat of fusion to melt the ice, which is still smaller than the heat of vaporization, but starting to become somewhat significant.
That is exactly what I have been taught, too, and when I mentioned it in passing to a doctor friend the other day his response was, “Yes, of course, I should have thought of that”.
I’d like a cite for your body expending energy to bring a drink up to temp. If you’re already overheated (ie sweating) I don’t think your body is going to kick it into overdrive trying to warm liquids up.
There are somethings your body seems to know naturally. People in the humid Southern states in the US seem generally inclined to drink iced tea in the shade if they are outside. Some may prefer lemonade or a cold beer. When I was a kid, we took out a bowl of ice, salted it down and ate it.
Sweetened iced tea was the one thing that I craved when I came back from Paris and I ordered a tall glass of it at the Philly airport. Best glass of tea I’ve ever had.
Imho, there’s a difference between being cooler and feeling cooler. I remember a radio trivia question: if you drink a pitcher of margaritas, does your body temperature go up or down? While the alcohol might make you feel warmer, your body actually decreases in temperature.
In my experience, if you want to cool down your body, use something cold. If you want to feel cooler, sweating from drinking/eating hot food could work for you, or, if your insides are warmer, you might feel cooler on the outside.
Personally, I prefer hot drinks on hot days, because when you buy a hot drink, you are probably entering a cold, air conditioned environment, like a Starbucks. A cold drink + cold air + sweating makes me too cold. I warm up my insides so I can enjoy the air conditioning longer. However, if I’m hot because I’m sitting in the sun, I prefer something cold.
Saying that drinking something hot makes you feel cool is like the old trick of hitting your thumb with a hammer to cure your headache. Having heated yourself up with the hot drink, of course you feel cooler later, after your body has finally gotten rid of the extra heat. And, having cooled yourself down with a cold drink, of course you feel warmer later, having warmed up after the drink is done cooling you.
But the bottom line is still that drinking cold beverages cools you down and drinking hot beverages heats you up.
I remember reading in an early 1950s era World Book Encyclopedia that drinking cold water when it’s hot makes you hotter because it “increases circulation.”
I also had a 3rd grade teacher who said that fanning yourself when it’s hot makes you hotter because “it evaporates your sweat, which is there to cool you down.”
Cool/cold liquids cool your body’s core temperature. Hot/warm liquids warm your core temperature. You don’t pour hot water on a heat stroke victim, nor do you pour ice water on a hypothermic person. Next question.
If that were the case, you would get into serious problem. You don’t want to mess with your body’s core temp.! The body spends a lot of energy precisly to keep the core temp. at the most constant rate possible. The outer temp. may vary a bit, but even then, it’s quickly “too much”.
Um, who said anything about heat stroke victim?? We were talking about normal persons! Heatstroke and Hypothermia are obviously extreme situations that require medical attention, not normal situations.
Hereis a first quote from a german newspaper (although they don’t give the source - usual for layman’s publications)
Apparently you didn’t read that article very carefully. 195 degree water freezes faster than water only around 140 - 175 degrees, but it didn’t mention water at a normal, out of tap temperature (say 40 - 60 degrees).
No one’s tap at home is set up to dispense boiling water (unless you have one of those instant coffee maker thingies like they have at hotels), so it would be pretty dumb to waste time and energy heating water to 195 degrees - 212 degrees just to put it in the freezer.
You also neglected to mention that you don’t end up with the same mass of frozen water in the ice cube trays…the boiling water lopst up to 16% of its mass to evaproation.
How do you find this out, however? What feels natural and sensible to you often is contradictory to what’s best for your body, or even what’s really happening in your body. For example, in winter, drinking alcohol makes you feel warmer, so many people assume it’s a good aid measure for hypothermia.
In reality however, alcohol dilates your blood vessels, countering the natural mechanism of your body (constricting blood vessels on the surface to conserve heat for the core), and you end up much colder afterwards because you lost too much heat. (The mythbusters tested this with infrared cameras and thermometers).