As a former endurance athlete who specialized thru my 50s & 60s racing very successfully in the heat, by being precisely aware of the line between just being hot & heat stroke. That, as in running a howitzer requires adaptation to allow the body to function in that much heat which takes weeks,not days of measured exposure... the need for adaptation is perhaps a key factor in the survival,or lack thereof of folks w acute exposure to very hot environments w unaccustomed work loads
A key ingredient, the same for the marine loading the 155 shells is adequate water and electrolytes.

Racing in 95+F sunny weather I routinely consumed 3 20 water bottles/hr. Also, one must take in adequate salt, esp NaCl & magnesium along w enough water. IF the work load is high enough, then you must ingest fluids regularly, not wait for thirst

 

Straight water is not enough. It's a very good start, but it's not enough in high heat environments with moderate work load. You need to be replacing electrolytes to be able to continue functioning.

This is why UF developed Gatoraide back in the day. Not endorsing that particular product, there are many. But I can personally attest to how well Gatoraide works when it's needed.

 

Even though I prefer extreme cold to extreme heat, extreme cold is probably a worse condition to have to function under as a soldier. Water is less important and you can eat snow as long as it's not yellow.

 

Physical exertion is in hot, humid climates is pretty miserable for me. Being stationary in freezing weather is pretty bad.
IIRC growing up in a hot climate gives you more sweat glands and those that grew up in colder areas will never have as many. If you spend time in the cold you will develop more brown fat and that will warm you as long as you have the calories, those raised in a warm climate can adapt to the cold better than the other way around.

 

You have to ride the line between keeling over and sustaining activity a few times before you get to the point that you are even capable of exerting yourself for extended periods of time in high heat.

Once you've done that, you can live a long time with unlimited water and some electrolitic minerals and enough food to sustain yourself for a long time.

As to the question of whether the average person can do that or not, it would seem that less than half the population even has the mental resilience to do that--and mental resilience really is the issue.

 

Yeah, the impetus for this question was reading about all the people who decide to go hiking in the desert and end up dead. My first reaction is, "how much water did they have?"... because that would be the first question asked in the Marines when I was in... you got water? This was post Jason Rother and it could very well be that the simplest thing they could boil it down to was... water.

I get the point on acclimatization... which we really did not do... and the unit from up in Yakima WA had a hard time; constant heat casualty helicopter rides.

The units from down in Pico Rivera and Jackson Mississippi fared better. For some reason, those of us from the comparatively cool SF Bay Area did fine as well, although, as an HQ Btry, we were not humping rounds, so the physical exertion levels for us was way less (but still more than just going on a day hike).

 

I remembered a very young me doing one of those corporate team building projects where you have to survive a hike and assign everything a priority. I was the only person who highly prioritized fluids and then food.

I’m not saying other people weren’t smart. But like you said “did they bring enough water” is like the easy go-to. For surviving outside anyway. I think some people who either don’t understand / know their own limitations or have no experience to fall back on it can be fatal.

I ran outside today. It was a “cool” 84F.

 

 

Plants like electrolytes!

 

Granted, most of us are not humping 155 shells into M198s in an attempt to fight a notional enemy...

But some of us were.

I think it matters what you're doing and what the total circumstances are. I mean if you have unlimited water you can jump in every so often and cool yourself off

 

Nope. Most of us would Croke. Including me.

 

We fought the extreme heat in Iraq, I don’t know how they did it in Vietnam with the humidity. As light infantry we could only carry enough water for four hours then we needed resupply. It was brutal.

I wouldn’t even try it today (that was 20 years ago) nor would I have the constitution to spend a week in the field with the negative temps they face in Korea or WWII. It’s amazing what you can do if you have no choice I guess. We had to have high calorie MREs along with water. Even then, after raids we were giving each other IVs back at the FOB

 

We fought the extreme heat in Iraq, I don’t know how they did it in Vietnam with the humidity. As light infantry we could only carry enough water for four hours then we needed resupply. It was brutal.

I recall some really cold times up in the guard tower (FOB Highlander) on winter nights.

 

Ambient 110F under the Arizona sun, where I live, no.

 

How about -40?

 

When I lived in AZ I was comfortable hiking and canyoneering up to 110. Above that was debilitating and unpleasant for me. I did prefer extreme heat to the frost bite I acquired mountaineering.

 

You have great stamina! How many gallons of fluids did you carry while hiking?

As I previously posted, under the Arizona sun, on this day, ambient temperature was 106F...

Scorching heat in the US Southwest kills three migrants in the desert near the Arizona-Mexico border

Three Mexican migrants have died in the Sonoran Desert in Arizona near the U.S.-Mexico border. The deaths come as temperatures hit the triple digits across parts of the Southwest.

apnews.com

645 deaths in Maricopa in one year

 

The biggest problem I have with this theory is assume the health of an individual. Most people who are presently healthy may still be technically overweight and obese.

For laughs sake. I am Florida man. Garmin says "heat acclimation starts at 72 degrees" which is laughable because I keep my AC set to 77-78 most days in the summer. I usually run outside 1-3x a week and run on my treadmill when the weather says naw which in Florida can be often or not at all. Nobody in my peer group except my sister has even attempted to run outside this summer. Typically and this includes electrolytes I am making sure that I drink enough to go to the bathroom. Most people don't do this.

I want to say that if acclimation period was long enough that it would be probable for most people. But assuming zero heat acclimation I would expect casualties and or a very rough start for many. As others have said, electrolytes, suppluments, and diet also becomes important too.

 

The bottom line is really thermo-regulating your core body temperature. As I posted above, water is obviously necessary. But in high heat environments we lose body salts through perspiration. If those electrolytes aren't replace the body's ability to thermo-regulate core body temperature is compromised. Something as simple as squeezing half a lemon into 16 ounces of water goes a LONG way towards restoring balance. As @battousai states above, most people don't drink enough to begin with. If you aren't peeing or the urine is dark and cloudy then you are already dehydrated and are in the position of having to play catch up.

 

Pre-GWOT, when I was working in Kuwait, units would rotate in from the States, draw equipment (vehicles, weapons, and other such stuff, and then drive out to the desert and spend 60+ days playing Army. One unit that rotated in during early September one year, sustained 300% heat casualties on their first day, which is all admin stuff - inventorying and drawing equipment, etc. They had all the water that they could drink, but they were not acclimatized to the incredibly hot and HUMID weather during that part of the year. I don't recall their point of departure Stateside, but it obviously did not prepare them to be working in the sauna.

 

At 37 I moved from Buffalo to Florida - my first day was on Aug 1st and I thought I was going to die. 90 plus degrees and the humidity was thick. It took me several weeks before I started to feel comfortable while outside. It got better the longer I lived there. When I visited AZ for the first time the highs were 105-110. I ended up taking a 3 hr hike into the foothills of the Rincons - no problems. I was 50. I moved to AZ three years ago at age 63 during one of the hottest summers. The following summer was worse with daily temps breaking records, longest streak of temps over 110. Daily humidity was 5-10% max. It was rough. Exercise started at 4:30 - 5am to be tolerable. Morning lows starting in the mid 80's at those times. 100 degrees by 9am. This summer is better but I finally (two weeks ago) decided enough. I moved my morning 1 hr walks inside to a more comfortable 78 degrees. Hours outside in the middle of the day in direct sunlight would fry me. Pavement temps exceed 145 degrees daily. I drink a lot of water and back it up with Gatorade during exercise, but doing anything strenuous for long periods of time wipe me out.

 

No. At a certain level of cold you will die! Hot, yes, cold....no.

 

At a certain low temperature you freeze to death. It happened to several German soldiers in WW2. My wife's grandpa would rarely talk about it. But, he came upon a nazi standing guard. He pulled his knife out and stabbed the man. He said he was already dead. He froze standing up. I had a heat stroke. Working in a plastics company. In the summer we would see 140 degrees in that plant. I drank a gallon of water and some Gatorade that morning. I couldn't hydrate fast enough. If we'd had a company nurse on duty. They could at least start you on iv fluids in the ac break room. Like soldiers have medics. You can survive more heat than cold. If you have decent health. IMO. However I'm not an educated person on this matter.

 

but could your average person safely function, out and about, moderately strenuous activity, for a day in 110F assuming you had an adequate supply of water on hand?

Probably not tending to definitely not. The only test of which I am aware was in the Israeli army In contrast to the old USMC doctrine of rationing water, the people marching from the northern tip of Israel to the southern point were encouraged to drink water. They arrived and functioned very well.

Is your "average person: (house wife/ guy who hasn't run a mile since high school) able to run one mile at 79 degrees Fahrenheit, drinking as much water as possible? Humor. Decades ago, I had a conversation with an older guy. He was complaining that he had a diagnosis of asbestos infection affecting his breathing and he could not longer run 5 miles a day. So I asked him if the last time he ran 5 miles a day was in 1946 when he was a paragrooper? "Yes".

 

Short answer; No.
Heat illness and dehydration are two distinct but often related problems.

 

You can generally remain cool enough to survive by inactivity.

Earth experiences cold that can kill you no matter how active.

 

Even today cold still kills far more folks in first world countries than heat. It's only going to get worse. The elderly that survived their planned demise from the covid protocols, now increasingly can't afford winter heat since the greening of the energy sector has increased electricity rates in some areas of the US & Northern Europe 400%

 

That's no lie. I live in MO. No where near the hottest state, we have insulated windows and run the attic fan when we can. Our electric bill was $700 for August. If it gets any higher. I'll have to sell our house and buy a trailer and haul it around. Go north in the summer and south in the winter. Be like the nomads and travel with the herds.

 

Ha! That’s what it was!

 

I also took summer vacations to 29 palms. Free room and board. Good times… I’d rather be there than somewhere freezing cold.