Physics filter: Sweat alternatives outside water
July 3, 2022 5:19 AM Subscribe
I don't sweat. I have anhidrosis / hypohidrosis. Is there a liquid I could put inside my sweat-alternative water bottle that would work better than water?
Like, should I put salt in the water? Or sugar?
Alcohol evaporates quickly (hand sanitizer feels colder than water on my hands). Would adding everclear make it more effective?
Surely we have things that are better at evaporating than water, but maybe they have a lower specific heat. In a hypothetical world would antifreeze or refrigerant work better? Is there something I could add to water to make it work slightly more like those?
Is there a physics answer here, keeping in mind cleaning the bottle and cleaning myself are also important, and that I'll probably be applying to my skin (and eyes?)
Like, should I put salt in the water? Or sugar?
Alcohol evaporates quickly (hand sanitizer feels colder than water on my hands). Would adding everclear make it more effective?
Surely we have things that are better at evaporating than water, but maybe they have a lower specific heat. In a hypothetical world would antifreeze or refrigerant work better? Is there something I could add to water to make it work slightly more like those?
Is there a physics answer here, keeping in mind cleaning the bottle and cleaning myself are also important, and that I'll probably be applying to my skin (and eyes?)
Antifreeze is toxic and the advice is to wash it off with soap and water if it gets on your skin. It's not actually terrible if it gets on your skin, but I would be more concerned that wandering around with a spray bottle of antifreeze wouldn't help but could lead to someone accidentally ingesting some of it.
A number of cooling products essentially work by stripping the top layer of skin cells off which means repeated use would rapidly transition from a sensation of coolness to a sensation of pain. Highly volatile chemicals like alcohol, gasoline and eucalyptus work by evaporating quickly, but their volatility means that they also penetrate and damage the skin. The damage with alcohol may be minor but it destroys bacteria. Just a little more time and effort and it is destroying skin cells as well.
posted by Jane the Brown at 6:04 AM on July 3, 2022
A number of cooling products essentially work by stripping the top layer of skin cells off which means repeated use would rapidly transition from a sensation of coolness to a sensation of pain. Highly volatile chemicals like alcohol, gasoline and eucalyptus work by evaporating quickly, but their volatility means that they also penetrate and damage the skin. The damage with alcohol may be minor but it destroys bacteria. Just a little more time and effort and it is destroying skin cells as well.
posted by Jane the Brown at 6:04 AM on July 3, 2022
Consider coming at it from the other end and reduce the rate at which your damp clothes dry out again. Cooling technology exists and while the idea in general is to use your sweet to create the effect you can use water.
posted by koahiatamadl at 6:28 AM on July 3, 2022
posted by koahiatamadl at 6:28 AM on July 3, 2022
When horses get dangerously overheated in competition (for example, endurance races) they sometimes cool them down with a 50/50 mixture of rubbing alcohol and water. It is somewhat drying so you would want to keep up with a moisturizer routine. Focus on the parts of the body with lot of blood vessels close to the surface--wrists and inner arms, for example. If it's feasible, I would suggest a spray bottle with an alcohol mixture for neck-down spraying and then wearing a chiller hat or headband or the like dampened with plain water to help keep your head cool.
posted by drlith at 6:44 AM on July 3, 2022 [1 favorite]
posted by drlith at 6:44 AM on July 3, 2022 [1 favorite]
Response by poster: Jane the brown, this is the most helpful advice I have found about my condition after months of searching. Thank you so much. I'm going to change my current running routine (which gives me heat exhaustion every time) to try to swim more. A whole new rabbit hole for me!
To the rest, thanks for your thoughts. I have used a cooling towel, but it doesn't stay in place very well. I'm going to research other cooling products that I can also use.
posted by bbqturtle at 6:52 AM on July 3, 2022 [7 favorites]
To the rest, thanks for your thoughts. I have used a cooling towel, but it doesn't stay in place very well. I'm going to research other cooling products that I can also use.
posted by bbqturtle at 6:52 AM on July 3, 2022 [7 favorites]
I agree with the above comments that you want to stick with regular water. Also, swimming for exercise can really help with this issue.
In warm weather are you trying to use cooler water? Can you use some kind of insulated water bottle and add some ice to keep the water cooler? Are we talking about a dry climate or more humid climate? In a hot and humid climate it can sometimes be hard to get good evaporation going of the water that you apply to help with cooling, so one of those mini portable fans might help with that evaporation when you are out and about.
Are you using one of those hats that you can wet, or that have an insert you can keep wet?
My old friend who rides horses in the hot southern U.S. swore by wearing a cooling vest. Cooling vests are available in pull over or zippered varieties. One kind is submerged in water before wearing, and as the water evaporates, your body is cooled. Another type of cooling vest uses inserts that can be placed in the freezer or cold water prior to use. There are also hybrid vests that mix the two technologies. I don't remember which kind my friend has used, but you can google something like equestrian cooling vest or cooling vest for riding and come up with some products.
posted by gudrun at 6:59 AM on July 3, 2022
In warm weather are you trying to use cooler water? Can you use some kind of insulated water bottle and add some ice to keep the water cooler? Are we talking about a dry climate or more humid climate? In a hot and humid climate it can sometimes be hard to get good evaporation going of the water that you apply to help with cooling, so one of those mini portable fans might help with that evaporation when you are out and about.
Are you using one of those hats that you can wet, or that have an insert you can keep wet?
My old friend who rides horses in the hot southern U.S. swore by wearing a cooling vest. Cooling vests are available in pull over or zippered varieties. One kind is submerged in water before wearing, and as the water evaporates, your body is cooled. Another type of cooling vest uses inserts that can be placed in the freezer or cold water prior to use. There are also hybrid vests that mix the two technologies. I don't remember which kind my friend has used, but you can google something like equestrian cooling vest or cooling vest for riding and come up with some products.
posted by gudrun at 6:59 AM on July 3, 2022
Also from experience riding - I love my sunshirts so much, they manage to be cooler than exposed skin.
For reasons I've never understood, beer (usually Guinness) is a treatment for horses with anhydrosis. Not medical advice, but maybe amusing.
posted by sepviva at 7:42 AM on July 3, 2022 [1 favorite]
For reasons I've never understood, beer (usually Guinness) is a treatment for horses with anhydrosis. Not medical advice, but maybe amusing.
posted by sepviva at 7:42 AM on July 3, 2022 [1 favorite]
A couple tangential tips since you asked: my husband is extremely heat-sensitive and swears by Mission's cooling hoodie, which he holds on with a velcro-adjustable visor because of a large noggin but also to let it evaporate on his head without moving around. When it's really hot, especially if it's a little humid, he wears a neck fan under the hood to increase cooling.
I am stalking the Mission website waiting for their full recovery towel with hood to come back in stock.
I just don't think there's anything you can add to your spray-water that wouldn't be a worse trade-off in skin irritation or ruining your clothes (and probably making them uncomfortable at the time).
I agree that swimming is probably the best rabbit hole to go down. I am one of those people who turns beet red the moment I begin any exertion and when swimming I can feel the heat leeching off my head in the water.
posted by Lyn Never at 8:02 AM on July 3, 2022 [2 favorites]
I am stalking the Mission website waiting for their full recovery towel with hood to come back in stock.
I just don't think there's anything you can add to your spray-water that wouldn't be a worse trade-off in skin irritation or ruining your clothes (and probably making them uncomfortable at the time).
I agree that swimming is probably the best rabbit hole to go down. I am one of those people who turns beet red the moment I begin any exertion and when swimming I can feel the heat leeching off my head in the water.
posted by Lyn Never at 8:02 AM on July 3, 2022 [2 favorites]
FWIW there's a whole host of cooling products, some are more gimmicky than others.
If you search for "cooling vest" you'll find a lot of vests that lets you fill in with colder water (or even ice!) or have integrated cold paks that you can pre-freeze, and give you an hour or two or cooling in hot weather, which hopefully will get you through your exercise. Some of them are even hi-vis, thus great for running on public roads.
Someone already mentioned Mission, who has a whole series of caps and hats styles available in addition to other apparel. Basically, add some cool / cold water and they help you cool for up to 2 hours.
If you are willing to put up with a bit more weight, there are (battery-powered) neck-fans available that you wear around your check, and it'll blow a breeze at your face. Some models have an automatic sprayer, but I doubt they have a large reservoir enough to last 1-2 hours to finish your exercise.
posted by kschang at 8:20 AM on July 3, 2022
If you search for "cooling vest" you'll find a lot of vests that lets you fill in with colder water (or even ice!) or have integrated cold paks that you can pre-freeze, and give you an hour or two or cooling in hot weather, which hopefully will get you through your exercise. Some of them are even hi-vis, thus great for running on public roads.
Someone already mentioned Mission, who has a whole series of caps and hats styles available in addition to other apparel. Basically, add some cool / cold water and they help you cool for up to 2 hours.
If you are willing to put up with a bit more weight, there are (battery-powered) neck-fans available that you wear around your check, and it'll blow a breeze at your face. Some models have an automatic sprayer, but I doubt they have a large reservoir enough to last 1-2 hours to finish your exercise.
posted by kschang at 8:20 AM on July 3, 2022
I have thick hair, and getting it quite wet and french braiding means it dries slowly and is cooling in summer. When it's really hot, I spritz my hair with water. I also spritz my dog, which she thinks is annoying, but tolerates.
When I took ADHD meds, I sweated much more; coffee may also increase sweating. I have no expertise, but coffee is easy to try.
posted by theora55 at 8:30 AM on July 3, 2022
When I took ADHD meds, I sweated much more; coffee may also increase sweating. I have no expertise, but coffee is easy to try.
posted by theora55 at 8:30 AM on July 3, 2022
What you can add to water to make it more effective is a breeze. A small portable fan would help, added to your squirt bottle would help and you can get squirt bottles with them built in. Also to make it more effective at cooling you may want to look at spraying it onto cotton clothing so that the moisture soaks through to your skin. The clothing could hold more moisture against your skin than on plain skin and hold it longer so you don't need to squirt as often, basically making your clothes a swamp cooler. This is why wet clothes are dangerous for hypothermia
posted by wwax at 9:15 AM on July 3, 2022 [1 favorite]
posted by wwax at 9:15 AM on July 3, 2022 [1 favorite]
Best answer: Yes, adding everclear to your water would help it cool you, but consider using dentatured ethyl alcohol, to cut cost. You could even use cheap vodka.
One aspect of adding alcohol to water and using that for external, evaporative cooling is that the solution will wet your skin better. Skin is naturally kind of hydrophobic, and resists wetting by water, at least at first, so wetting isn't very efficient: water runs off quickly. Alcohol in your water makes your water wetter.
Alcohol in some proportion will overcome this tendency, and allow the solution to wet your skin in a thinner layer, with less waste. A less volatile alcohol will be less unpleasant, in terms of accidental vapor inhalation and odor, so ethyl is better than isopropyl that way. Stay away from methyl alcohol, of course.
Specific heat is less important than heat of vaporization in this application. Specific heat of water is a 4.1 joules per gram per degree C. Heat of vaporization is a whopping 2400 joules per gram at 50 C, and more at lower temperatures. Heat of vaporization of ethyl alcohol is only 846 joules per gram, though, so if you use it to make your water wetter, you'll be derating the effectiveness of the solution as an evaporative coolant, but even with a 40% solution of ethyl alcohol you'll still be getting something like 1600 joules/gram. It's likely you'll get the wetting effect at considerably less than 40% by alcohol: you'll have to experiment.
Finally, as a personal anecdote, I've done something like this for decades on my skin, and have observed no observable ill effect (other than the hazard of people noticing the smell of ethyl alcohol, and presuming that you are an alcoholic). I use it on tender skin, and have observed no irritation, and perceive no "buzz" from alcohol from putting it on my skin.
posted by the Real Dan at 12:59 PM on July 3, 2022 [3 favorites]
One aspect of adding alcohol to water and using that for external, evaporative cooling is that the solution will wet your skin better. Skin is naturally kind of hydrophobic, and resists wetting by water, at least at first, so wetting isn't very efficient: water runs off quickly. Alcohol in your water makes your water wetter.
Alcohol in some proportion will overcome this tendency, and allow the solution to wet your skin in a thinner layer, with less waste. A less volatile alcohol will be less unpleasant, in terms of accidental vapor inhalation and odor, so ethyl is better than isopropyl that way. Stay away from methyl alcohol, of course.
Specific heat is less important than heat of vaporization in this application. Specific heat of water is a 4.1 joules per gram per degree C. Heat of vaporization is a whopping 2400 joules per gram at 50 C, and more at lower temperatures. Heat of vaporization of ethyl alcohol is only 846 joules per gram, though, so if you use it to make your water wetter, you'll be derating the effectiveness of the solution as an evaporative coolant, but even with a 40% solution of ethyl alcohol you'll still be getting something like 1600 joules/gram. It's likely you'll get the wetting effect at considerably less than 40% by alcohol: you'll have to experiment.
Finally, as a personal anecdote, I've done something like this for decades on my skin, and have observed no observable ill effect (other than the hazard of people noticing the smell of ethyl alcohol, and presuming that you are an alcoholic). I use it on tender skin, and have observed no irritation, and perceive no "buzz" from alcohol from putting it on my skin.
posted by the Real Dan at 12:59 PM on July 3, 2022 [3 favorites]
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When I use a spray bottle to stay damp and cool the problem seems to be that it evaporates too quickly and I need to spray myself yet again. Theoretically if I sprayed myself with an alcohol solution it would evaporate that little fraction quicker and need to be sprayed even more often... Truth is water seems to evaporate at the best speed to cool the skin. Alcohol goes so quickly there is a momentary flash of cool, gone in an instant.
Basically your skin evolved to deal with getting wet with rain, so you can easily handle being sprayed with basic water, but additives are likely to introduce other issues. Some people have trouble with being exposed to brine - it is notoriously hard on the hands if you have to use it for laundry or house cleaning in the absence of fresh water, and it will leave a residue of salt crystals. I don't think salt on the skin would help your electrolyte balance, especially where you are not sweating and therefore not losing salt through your pores. If you have anhidrosis your salt needs are going to be a lot lower than someone who sweats copiously.
Cross channel swimmers and others who swim in very cold water coat their bodies with grease before they swim because it helps them retain body heat. I'd therefore assume that adding some grease/oil/lotion to the mix is going to make the water less effective.
So bottom line, no, I think plain water is going to be most effective.
I suspect you already use cooling towels etc in strategic places. I find dunking my head repeatedly to be quite effective. In bad weather every ten or twenty minutes helps. You need the right hair cut and style to get away with this.
You can train yourself to sweat a little bit more by doing intensive heavy swimming. Being in water means that you don't overheat before you produce and sweat, so your pores adapt to producing sweat more easily. But you have to keep it up, and it has to be at a level of intensity that would make a person without anhidrosis sweat hard. On the other hand swimming is one sport that someone with anhidrosis can actually do without collapsing from heat stress, so is the first one to consider if you are looking at a cardio-vascular program.
posted by Jane the Brown at 5:56 AM on July 3, 2022 [16 favorites]