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Comment by pengaru | Hacker News Reader

"And it’s so dry that you barely sweat… a condition that conceals dehydration."

Without sweating I'd sure like to know what's happening to all that hydration...

It seems there's been a lot of stupid hyperbolic drama in the news lately about high desert temps and how unlivable they are.

But the reality is it's the non-arid regions that are unlivable in extreme heat waves.

Deserts are so dry it's trivial to stay cool enough to survive. All it takes is shade and water, perspiration and evaporation takes care of the rest.

You can't do the same with so much humidity the sweat can't carry the heat away from your body. That's what kills people.

(I own land in the Mojave by JTNP, on which I'm presently spending yet another AC-less summer. I wouldn't dare do this in muggy IL, but here it's really no big deal - I just get less work done outside having to stay in the shade.)

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Yes, this is exactly right. The wet bulb temperature in parts of Texas and Florida in the heat wave a week or two ago got close to the limit of human survivability. Five years from now Texas, Florida, the Persian Gulf, and South Asia are all going to be seeing that limit exceeded at least briefly every summer.

I was in New Mexico a while back, and being outside walking around in 35 C heat was completely comfortable because of how dry it was. Relative humidity less than 20%. It's so dry that the heat index (by the National Weather Service's formula) is actually less than the true temperature.

By comparison, life at 60% humidity in the Northeast at 30 C is considerably more miserable without air conditioning. Without a fan blowing in my face constantly to improve evaporation, my head starts to feel like mush after about an hour.

Conversions: 35 C = 95 F, 30 C = 86 F

Definitely. The only place in the deserts in the US that will be an exception to this is Yuma AZ because it is close to the warm ocean waters to the south of it so it's more humid. But it doesn't have a huge population unlike Houston or Miami.

I think the writer means that the sweat evaporates so rapidly that it does not feel like you are sweating. That is, you don’t get drenched in sweat. I think during heat exhaustion the body stops sweating. Perhaps it’s easier to miss the signs of impending heat exhaustion in such conditions.

It's really not, your mouth and throat become parched at that point, it's a very clear indicator you need to hydrate.

Needing to hydrate isn’t an indicator of impending heat exhaustion. I mean, people need to hydrate sometimes in cool weather. The Mayo Clinic doesn’t list needing to hydrate as one of the symptoms to be on the lookout for.

I’m not a doctor. I’m just surmising that if you aren’t drenched in sweat because it has evaporated so fast that one might not be aware of impending heat exhaustion. Obviously I might be wrong. Heavy sweating is a possible symptom of heat exhaustion.

https://www.mayoclinic.org/diseases-conditions/heat-exhausti...

Edit: At the end it does list dehydration as something to look out for. I have no idea what it is like in 110 degree weather with virtually no humidity. I’d guess even being well hydrated still makes it easy to get heat exhaustion.

Yeah I tripped over that line too. I think maybe they meant you don't realize you are sweating excessively because it evaporates so fast which causes dehydration. Compared to a high humid area where you'd be drenched in sweat and realize you need to hydrate.

They clearly mean that rapid evaporation prevents sweat from accumulating on the skin, making it easy to miss rapid loss of water since you don't feel it very much.

Given that you explain exactly this, you seem to have understood it. If your biggest concern with this story is a relaxed use of the word "sweating" you might want to go back and reread it.

The problem is they're characterizing it like this is a negative thing, which only makes it further appear as if they don't know WTF they are talking about.

That quick evaporation of your sweat is a feature of the desert, and it's why you won't die in 120+F.

The article is trash

You won't die... if you drink a gallon of water a day, and get enough electrolytes. If you don't, though, 120F can certainly kill you.

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