It was a firm belief of my mother that “No one ever drowned in sweat.” Just in case, she taught us to swim though. And she taught us the basics of today’s topics…I admit I’ve supplemented that a bit from being a biology geek. That said, I’m still not a physician, so take this as a discussion of a topic, not medical advice.
Americans have gotten very used to being able to hang out in a nice air conditioned space when the heat rises. If that becomes unavailable, that’s a problem. There was another article here on BBBY recently about strategies for not overheating. This one’s about how to recognize when overheating has occurred, and what to do about it if ‘Call 911’ isn’t a viable option.
If you feel like the cactus, but you’re not wise about keeping cool…
…You could explode into a cloud of dust like this poor guy. Or (more likely) suffer heat injury.
There are three stages of heat injury, each worse than the last. Basically they are:
- Sweated too much: Heat cramps
- Sweated way too much: Heat exhaustion
- Couldn’t sweat enough: Heat stroke.
Hey look, they even arrange themselves in alphabetical order for our convenience!
The basic biology of it: We sweat to cool ourselves. In order to coax the water to the surface so it can evaporate and cool you, you lure it by pumping out ions (the things that make up salts). So when you sweat you lose water and ions. Your brain and muscle cells work by moving ions around, so losing too many ions fouls up brain and muscle function. The water you lose comes from the blood, so if you lose too much of that there’s too little blood left and circulation flags.
Heat cramps occur when you’ve been sweating a lot to cool yourself, and it’s worked so far, Yay! But you’re running low on water and/or ions now. That gives your muscles an ‘itchy trigger finger’ as it were, and cramps result. Diagnosing this one is not brain surgery. “Oww Owww, big painful knot in my muscle and I can’t move the leg right!” The smart money is on cramps. The cramps are mostly likely to hit at night after a day of lots of work and sweat. Mine lie in wait until the drop in blood flow that comes with almost falling asleep, then a slight change of position and they Attack!
Heat exhaustion is a similar mechanism, but strikes during the exercise. It’s mostly due to the water loss. The skin gets a pale and moist, the heart races, the person may be dizzy and disoriented and definitely feels weak. There’s a lot of sweat. Heat cramps may co-occur. Standing up is likely to provoke faintness and tunnel vision … that’s about one half breath away from passing out.
For either cramps or heat exhaustion, it’s clear you’ve got to replace the water and ions. I find salty foods and water more effective than sports drinks. My body seems to know this; I’m normally not a food salter but after a day of sweaty work you’d have trouble prying the salt shaker out of my hands. For heat exhaustion, the big thing is don’t be stupid and just try to ‘man up’ or whatever and push through it. It’s not a ‘push through’ thing; willpower will not trump too little blood to the brain. A seat in the shade with fashionable accessories such as wet towels on the head is the smart move. If you disrespect heat exhaustion it can lay you out or push you into heat stroke.
Big strong men get heat injury too…actually more easily than the scrawny but heat adapted.
Heat stroke occurs when the cooling mechanisms have been insufficient and body temperature’s gone dangerously high (104 F or more). Heart races, breathing is rapid, the skin is deeply flushed as the body tries desperately to dump the heat. The person may sweat a lot too, or the skin may go dry as shutdown begins. Headache, nausea, and vomiting may accompany as signs of the physical stress. The brain is starting to malfunction like an overheated computer, so changes in mental state occur …and it ain’t a change to being able to calculate cube roots in your head. Confusion, poor coordination (shows up as slurred speech), agitation, delirium, seizures, and coma follow. Death is not that far behind coma, so this is not a path you want to be on.
If emergency med help is available, call it. This is not something to play with. But if the person’s alone, they better hope for a cloudburst. It’s all about cooling; and cooling on hot conditions is all about getting out of the sun but not the wind and getting the person wet. Wet cloth is great if there’s a wind (remember the battery operated fans from a previous post?), with the head, neck, wrists, and groin being target points because of all the hot blood close to the surface in those places. If ice is available … now’s the time! A kiddie pool full of fresh pulled well water would be a blessing. Any diver knows that water that’s even a little cooler than the body sucks heat (water conducts heat away 25x more efficiently than air.)
Now That’s better! Thanks to By U.S. Army [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons for the image
Besides these ‘big three,’ there’s one other heat-related problem that gets overlooked: Potassium depletion. Potassium is an ion. You lose it when you sweat; not as much as you lose sodium, but some. If you’re being careful about replacing salt (with its sodium and chloride ions) and water, it might be potassium that runs low first. Muscle weakness accompanied by a tremor is the main early symptom. That’s as far as it usually gets from heat injury. (Kidney problems or extreme vomiting or diarrhea can mess up potassium more deeply, but that’s not today’s problem.) The doc who takes care of my sports teams gives us potassium gluconate tablets when we get ‘the quiver’. Lite salt (a 50:50 mix of sodium chloride and potassium chloride) can be used in place of regular table salt, including for cooking, too.
Lite Salt has as much potassium as sodium and may be used in place of ‘normal’ salt.
If you’re on blood pressure drugs ask your doctor before supplementing with potassium. Some blood pressure drugs interfere with potassium removal and you can collect too much.
Prepping for heat injury:
Once again, the best way to win is not to play. Thin and breathable but long-sleeved shirts coupled with wide-brimmed hats keep the sun off and help sweat evaporate. Cold packs in the med kit are useful. Having water to spare and that bandana that oughta be in the kit is good.
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Good article, thanks for writing it!