dry heat vs. humid heat: i went to arizona and hardly peed

writer nick beare investigates why 40-degree arizona heat caused his eyes to dry out, chapped his lips, and made his throat feel like "the inside of king tut’s sarcophagus."

by nick beare

published jun 14, 2022

4 minute read

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4 minute read

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dry heat vs. humid heat: i went to arizona and hardly peed

while the body cools itself a little easier in dry conditions, it doesn’t mean it is exempt from the dangers that extreme heat can present. getty

i recently took a golf trip to arizona with some friends, and outside some beautifully rugged landscapes, friendly people, and a heck of a lot of cacti, my main take away was this: it was hot. but any time you talk about travelling in the southwestern united states, you can’t mention how hot it is without someone chiming in to say, “but, it’s a dry heat.”

but what does that even mean? 40-degree heat is 40-degree heat, right? after all, i didn’t think the baking temperature would be that different from toronto, and yet, my eyes were dry, my lips chapped, and my throat felt like the inside of king tut’s sarcophagus. in fact, i had to keep drinking water to keep my tonsils from feeling like they were shrivelling up.

part of my experience may stem from the fact i have sensitive skin, but that wasn’t the only weird phenomenon. the other thing that happened to everyone i was with was that, well, we didn’t pee — despite playing golf in extreme temperatures for several hours and drinking litres and litres of water.

surely the dry heat to blame, but where did all the liquid go?

dry heat vs. humid heat

dry heat is often caused by mountains. in fact, some of the driest places on earth (the sahara desert and the australian outback, for example) are surrounded by mountain peaks that redirect humid air away from those areas and leave dusty, dry areas full of sand in the middle. the valley of the sun in the phoenix area is a prime example.

in southern ontario, we’re used to humid summers where it can often feel like you need to take several showers a day because your body is always sweating. but the lack of moisture in dry air allows the body to cool itself more efficiently with sweat — our body’s natural cooling system.

it didn’t feel like we were sweating very much in arizona. that’s because the sweat evaporates quickly in dry heat, allowing the body to feel cooler, faster, which created an odd sensation that we weren’t sweating a lot, despite the high temperatures. it also explains why my entire mouth, throat and face felt like a dried corn husk.

extremely dry air readily accepts any water and moisture from the things existing inside of it, so all the moisture on my skin and in my mouth was being sucked away by the dryness — which bring us to the pee.

even though it didn’t feel like we were sweating a lot, we were. and all that water leaving the body triggers the release of antidiuretic hormone (adh) into the blood. according to my health alberta, adh is a chemical created in the brain that tells the kidneys to release less water (pee) than they normally would. adh levels often rise at night so we don’t have to use the bathroom while sleeping, but they can also rise in the face of extreme temperatures. the body recognizes that there isn’t an excess a water available and goes into conservation mode.

if you drink a lot of fluids in more humid conditions where the body stays moist even while sweating, the body recognizes an excess of water, brings the adh levels down and tells the kidneys to release the extra fluids.

dealing with extreme heat

while the body cools itself a little easier in dry conditions, it doesn’t mean it is exempt from the dangers that extreme heat can present.

heat exhaustion and heat stroke are all serious conditions that could require immediate medical attention and it is important to know the difference, so you are able to respond in a timely manner.

with heat exhaustion, the person may be feeling dizzy or faint, is likely sweating profusely, could have a rapid pulse and muscle cramps while experiencing some nausea. if you or someone you are with has these symptoms, move to a cool, air-conditioned area and drink lots of water. taking a cool shower to bring the body’s temperature down can also help.

heat stroke is a more serious condition where the person stops sweating, has a serious headache, has red, dry skin with a rapid pulse and a body temperature above 103 degrees. someone with heat stroke needs medical attention. call 911 immediately.

consuming alcohol or doing any strenuous activity outside can also prevent the body from regulating its temperature correctly and put people at greater risk.

luckily for my friends and i, we were able to avoid any of the downsides of the extreme temperatures of the sonoran desert. but the next time someone says, “ya, well, it’s a dry heat down there,” i won’t be rolling my eyes.

nick beare is a toronto-based writer.

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