Yves here. This “news you can use” piece describes how animals, small children, and the elderly are particularly vulnerable to heat, how to recognize the signs, and what steps to take if you see signs of heat stress. It also lists some of the medications that increase the risk of hot temperature exposure.
By Jennifer Marlon, a senior research scientist at the Yale School of the Environment. Originally published at Yale Climate Connections
When temperatures soar, not everyone’s body handles the heat the same way – and for some, the risks can be severe.
Although heat waves threaten everyone, children, pets, and elderly family and friends face disproportionate dangers, each for distinct physiological reasons that every parent, pet-owner, and watchful friend should understand. And as climate change intensifies heat waves across the globe, understanding who faces the greatest risk – and how to help them – is a matter of life and death.
Children: Developing Systems Under Stress
Children’s bodies are fundamentally different heat-processing machines than those of adults. Their surface area-to-body weight ratio is much higher than ours, meaning they absorb heat from the environment more rapidly. Paradoxically, this same ratio should help them cool down faster – but their immature temperature-regulation systems can’t keep up with the demand.
Young children produce more metabolic heat per kilogram of body weight, yet their sweat glands are smaller and less efficient. They also have a higher core temperature threshold before sweating begins, essentially giving them a narrower margin of safety.
Infants face additional risks. Their kidneys are still developing, making them more susceptible to dehydration, while their larger heads and thinner skulls provide less protection for temperature-sensitive brain tissue.
Perhaps most critically, children depend entirely on adults for heat protection – they can’t recognize early heat stress symptoms, seek shade independently, or adequately hydrate themselves.
WHAT TO DO: Watch for signs like fussiness, decreased urination, or unusual lethargy, and immediately move children to cool environments while offering frequent small sips of water (or breast milk or formula for infants).
Pets: Silent Sufferers With Limited Cooling Options
Dogs and cats evolved different cooling mechanisms than humans, making them particularly vulnerable to our warming world. Dogs primarily cool through panting and limited sweating through their paw pads – far less efficient than human perspiration. Their normal body temperature runs two to three degrees higher than ours, giving them less buffer before dangerous overheating sets in.
Flat-faced, or brachycephalic, breeds such as pugs, bulldogs, and Persian cats face additional risks due to their shortened airways, which impede efficient panting. Dark-colored animals absorb more heat, while thick-coated breeds struggle to release it.
Unlike humans, pets can’t communicate their distress clearly or take protective actions like removing clothing or seeking air conditioning.
Ground temperature poses an often-overlooked threat. Asphalt can reach 150°F on a 90°F day, causing severe paw burns within seconds – a risk owners frequently underestimate because they’re wearing protective shoes.
WHAT TO DO: If you see your pet walking strangely, lifting paws repeatedly, or moving at an irregular pace, their paws may be burning. Immediately guide them onto grass, dirt, or into shade, and consider carrying small dogs on hot pavement. Devin Newman, a vet at Bush Animal Hospital in Eugene, Oregon, who is also my brother-in-law, says that if you cannot put your hand against the pavement for 10 seconds, then it’s too hot for a dog.
Don’t leave animals (or children!) in a hot car, even for a few minutes. Be mindful before breaking glass on someone else’s car, however, as some newer cars have a pet setting to keep dogs and cats comfortable.
Elderly: Aging Bodies, Diminished Defenses
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Aging brings multiple changes that reduce the body’s heat tolerance. As people age, their hearts pump less blood with each beat, making it harder for their cardiovascular system to move blood to the skin for cooling. Their sweat production declines, and their skin becomes thinner and less effective at temperature regulation.
Chronic conditions common in older adults – diabetes, heart disease, kidney problems – can make it harder for their bodies to stay cool. Many essential medications, including diuretics, beta-blockers, and antihistamines, interfere with the body’s natural cooling system or increase dehydration risk. Changes to a person’s memory and thinking patterns can make it harder to notice heat danger signs or know how to respond appropriately. Living alone may leave elderly individuals without help during dangerous heat events, while fixed incomes might force impossible choices between air conditioning and other necessities.
WHAT TO DO: Check on elderly relatives or neighbors daily during heat waves. Ensure they have access to air conditioning or cooling centers and help them identify early warning signs like dizziness, nausea, or confusion that warrant immediate cooling and medical attention.
The Climate Connection
These vulnerabilities matter more than ever because extreme heat events are becoming more frequent, intense, and prolonged. What were once rare heat waves are becoming regular summer occurrences, and previously safe temperatures are becoming dangerous when sustained over days. Understanding these distinct risk factors empowers us to protect our most vulnerable loved ones through targeted prevention – from never leaving children or pets in cars to ensuring elderly relatives have cooling plans and social check-ins during heat waves.
In our rapidly warming world, this knowledge isn’t just helpful – it’s essential for keeping our families safe.
As our esteemed correspondents from the Carolinas also note, the humidity has an important effect on how well our sweating cools our bodies. Sothron climes with high humidity will subtly increase the dangers of overheating by both masking absolute heat and decreasing the rate of heat exchange our skins can achieve.
Another aspect of high sweat rates is the loss of electrolytes via the sweat. People will become faint during high heat events through depletion of essential minerals, such as potassium, that happens when we sweat profusely. That is the secret to Gatoraid and related “sports drinks.” A football coach at the University of Florida asked faculty members at the Medical School to devise a solution to the dehydration effects his football players were experiencing. They discovered that if they fed his players a sweet drink loaded down with minerals, they performed better on hot days. Their solution was a solution.
Gatoraid: https://en.wikipedia.org/wiki/Gatorade
Stay safe, stay cool, in all its meanings.
A less palatable but much less costly, on a per-gram-dry-electrolyte basis, alternative to Gatorade or similar pre-mixed drinks is dry oral rehydration salts. I have been using “TriOral” brand for nearly a decade. Current price, in 100-pack size (each packet contains 7 grams of sodium and potassium salts, and 13 grams glucose, and makes 1 liter of electrolyte drink) is $0.40 per pack, up 1/3 since the beginning of the pandemic.
My trainer, who trained and rehabbed elite athletes (professionals, Olympic contenders, Division A participants) was part of a mafia of MDs who treated the same level of athlete and were fetishistic about reading studies.
They recommended against Gatorade pretty forcefully. It’s not better at hydrating than water. Its level of sugars offsets the electrolyte benefits.
This somewhat qualifies their take:
https://www.quora.com/Since-Gatorade-claims-to-hydrate-people-better-than-water-shouldnt-everyone-drink-gatorade-instead-of-water
An ol’ school answer is pickle juice for cramping muscles and dehydration.
I like that!!!
There have been times at the end of mountain bike rides we’d be cramping so bad it’d be hell to drive my manual tranny Tacoma the 3 miles with one traffic light to get to Publix. I’d open the jar in the aisle, drink the pickle juice, go pay for the pickles and by the time I got back to the truck the cramps would be gone. Now that I live 2 blocks from Santos my rides start and end from my back yard and my fridge all ways has pickle juice.
Ah. I knew there was a reason why I usually dilute my juices and “sports drinks” by half with water. Now it begins to make sense.
I checked and even the Gatorade cartel has caught up with the ‘science’ and now offers Gatorlyte. Electrolytes mixed in with lower levels of “sweetener.”
When I was foresting in my prime, August was the toughest month. The humidity was worse than the heat, and it’s not getting better. Some hard-wrung wisdoms:
: Flux. We figured this out during the blizzard, 72′ inside and we were still freezing. The temperature difference twixt inner wall and outside, plus the wind convection, meant the temperature looked good but the walls were draining heat from us. Heat index 105 with 90% humidity and no wind over 5mph did the inverse this last week. Sous vide.
: Ice cold at the base of the skull cools the brain, held in hand cools the heart. I have an ice-yoke I take from the freezer and put around my neck, brisk at first but I can lean my arteries into it.
: Salts as a pick-me-up: one package of tangerine EmergenC mixed with a teaspoon of Pedialyte Berry Blast powder and you get something like Brawndo. It’s got Electrolytes!
If it is an option, planting shady trees around your home might be a good idea – so long as they are not an easily flammable type like Eucalyptus. The shade helps keep the heat off your home and if you have a good type of tree, you can feel a few degrees drop in temperature when underneath them. Like has been found with Covid, to combat the heat will probably require a layered defense starting with outside your home and working your way in until you reach your skin.
A drop of caution here. In the last two years we’ve had explosive growth. This morning I pinned up a Black Raspberry wand 13 feet long. That is enormous, over twice normal.
We’ve gone to coppicing heights with our trees. Hurricane force winds are new, some of the growth seems spindly, and the local silver maples launch wind sails from on high. Full size limbs on a roof is a really bad day.
You can similarly feel the temperature drop when you get neat to or enter parks with a lot of tree cover, like Central Park, or residential complexes with a lot of trees.
Pro tip: if you’re in dry, hot farming country and need assistance, the farmhouse will almost always be located in a clump of trees. This PSA is provided without charge.
I see that in Oz as well to help alleviate the heat and I can see such a place from my back verandah. And of course the summer heat has influenced house design where I live with things like high ceilings, wrap-around verandahs and having the house raised up above the ground-
https://en.wikipedia.org/wiki/Queenslander_(architecture)
A timely and helpful article. Two things. The surface area to body weight ratio is lower in children than adults, not higher. Intuitively, a sphere has the lowest geometric ratio, and infants are more spherical than adults.
This indicates a 7.5x BSA increase to adulthood, whereas body weight increases at a larger multiple, increasing 10x by age twelve.Ref
Another factor, in terms of heat leading to dehydration: studies show that older adults, especially over 60, gradually lose their acute sense of thirst and may not realize that they are dehydrated until other indications occur.
biologyinsights.com/why-am-i-not-thirsty-reasons-and-when-to-worry/
In my case, I now drink proactively rather than by thirst.
News we can use! Proactivity is the way to go when you reach a “certain age.”
> In my case, I now drink proactively rather than by thirst.
I first heard the saying ‘Drink before you get thirsty’ many years ago and have followed its logic ever since.
Many years ago, but not many decades ago. That saying probably came from some marketing department. The whole hydration craze started after bottled water market became a thing (plain water in plastic bottles, to be exact), because it makes the sales go up. The Western Culture tend to be shaped by profits and interests, and not science, or even common sense. I have always been able to gauge my hydration level by the tone of my urine, which requires no additional effort since I have to look at it anyway, multiple times a day, for aiming purposes, being a male.
> Many years ago, but not many decades ago.
OK, not ‘many decades’; only three. Mid ’90s. My son came back with that slogan from summer camp. (And it stuck in our family.)
> That saying probably came from some marketing department.
He got it from one of the counselors, who repeated it often as part of the propaganda that also involved keeping their canteens full of tap water. Now, it’s true, this 19-year-old youth leader might have been an undercover corporate shill for the local public water utility, tasked with subverting the young ‘uns … just how, exactly?
A recent study from the Penn Vet Working Dog Center found that an effective core cooling method is a voluntary head dunk. Although studied because of the high risk of overheating for high drive working dogs that must at times work in high temperature and high humidity environments, when evaporative cooling from panting is reduced, and access to a large pool of water may be limited, the method is also being promoted for pet dogs by the AKC Canine Health Foundation (blog July, 2025) and by the American Veterinary Medical Association (press release Sept, 2024).
Comparing chemical neck ice packs, a wet neck towel, wet axillae towels, and a voluntary head dunk into 22-degree C water, the head dunk produced the lowest average core temperature in the five minutes after exercise. It was the only intervention to decrease core body temperature in the first 30 seconds, and it led to the lowest temperatures six to 40 minutes after the intervention.
This press release includes links to the 2024 paper and to an earlier 2023 study finding partial water immersion preferable to isopropyl alcohol on the paws as a cooling method. Both papers are open access. It also has a link to teaching the voluntary head dunk.
https://penntoday.upenn.edu/news/penn-vet-working-dog-center-reducing-dogs-temperature-after-exercise-voluntary-head-dunking
There’s some interesting advice here and, I also suggest people should consider how they dress. When I first arrived in the ME for work, I soon envied the Arabs who seemed to be dressed much more comfortably than any westerners.
In extreme heat you want to keep the sun off your skin. Jean shorts and t-shirt are not such a good idea.
Moreover, polyester and other synthetic fabrics, which trap heat, will likely make things much
worse. I don’t mean to dress like a Saudi when you need to get something at the Home Depot, but the Arabs have been living with extreme heat for centuries and being covered from head to toe in loose fitting clothing, preferably a natural fabric or a quality white cotton outfit is not the worst idea when you’re not inside with a/c.
RFK Jr hiked in the Phoenix foothills last week in 92 degree heat wearing blue jeans and looked like a sweaty pig in the photos I saw, which was a lot of levels of wrong-as cotton kills and having tight heavy pants on is something nobody I know would ever attempt even if it was 72 degrees and pleasant, you just don’t go there.
I’ve walked a shit-ton of miles in the usually sunny Sierra Nevada, and stopping in the shade for breaks is a must, and i’m quite the water drinker and sipping constantly from a 2 liter Camelbak bladder makes me gladder.