What to do in the next thirty minutes

If a dog is showing the signs Monday's piece described — fast, shallow, almost mechanical panting that does not slow when they stop; the tongue widening and curling at the edges; an unsteady, drunk-looking gait; an expression that no longer quite meets yours — then the question is no longer whether to prevent heat stroke. It is whether the next thirty minutes go well or badly.

This is the third piece in a heat-week series. Monday was about how to recognise an animal already in trouble. Tuesday was about the walks not to take, so that today's piece would not be needed. Today is the one we hoped you would never need: what to do if you find yourself looking at a dog or a horse who is already overheated, with no time to read anything long.

The summary is at the top of the piece so an owner who arrives here in the actual moment does not need to scroll. The reasoning follows. Read it in advance, not in the moment.

The short version

Move the animal into the deepest available shade or, if possible, into an air-conditioned room. Wet their belly, groin, armpits, inner thighs and paw pads with cool — not ice-cold — water. Direct a fan, an open window, or a piece of cardboard waved by hand across the wet skin. Offer small amounts of cool water to drink, but do not force it. Phone the vet now, while you are doing this, not after you have finished. Even if the animal appears to recover within minutes, take them to the vet today. Heat stroke causes internal damage that does not present externally for hours, and animals that "seem fine" can collapse twelve hours later.

That is the protocol. Below is what each step is for, what to do in what order, and what the well-meaning mistakes are that make it worse.

Why cool, not cold

The body's response to cold-water immersion is to constrict the blood vessels at the skin. This is what it is designed for: in cold water, you survive by pulling blood inward to protect the core organs. In a heat stroke, that is exactly the wrong response. Constricted skin vessels mean the heat that the dog is carrying in their core cannot move outward to the skin and dissipate. The hot blood stays in the core, where it is doing the damage.

Cool water — somewhere in the range of cool tap water on a temperate day, not refrigerated, not iced — opens the skin's vessels, allows blood to move outward, and allows the heat to come off through evaporation as the water dries. Ice baths look dramatic and feel like you are doing something. They slow the cooling process and, in severe cases, they can kill an animal that would otherwise have lived.

The same logic applies to ice packs. If you have them, place them under the armpits, into the groin and along the inner thighs — places where major blood vessels run close to the skin — and only for short stretches, ideally with a thin towel between the ice and the skin. Do not lay ice across the back. The coat insulates and the heat is trapped underneath.

Why the belly, not the back

A dog's coat is the single most important thing standing between you and effective cooling. On most breeds, hair traps heat against the skin; on heavy-coated breeds it traps a great deal of it. Pouring water over the back of a Bernese Mountain Dog is not cooling them. The water is sitting on top of an insulating layer, warming up, and effectively becoming a hot blanket.

The places to wet are the places where the coat is thin: the belly, the groin, the armpits, the inner thighs, the paw pads and the underside of the ears. These are also where the major blood vessels run shallow. Cooling the blood here cools the animal faster than anything else you can do at home.

For a horse, the same principle applies in scale. Hose the neck, the chest, the belly, the inside of the legs. Run the hose; do not stand it in. Use a sweat scraper to remove water from the coat after each pass. The repeated wet-then-scrape cycle pulls heat off the body in a way that a continuously wet horse does not.

Why airflow matters more than wetness

The single most effective home cooling tool is airflow over wet skin. Wet skin in still air does relatively little. Wet skin in a moving breeze gives off heat by evaporation, and evaporation is by some distance the largest mechanism the body has for losing heat. A fan pointed at a wet dog will lower their core temperature faster than a bathtub of cool water alone. An open window with air moving through it is better than air conditioning that is colder but still.

If there is no fan, wave a piece of cardboard, a folded newspaper, anything. The point is to keep dry air arriving at the wet skin so the water can continue to evaporate. A wet dog in still humid air is hardly being cooled at all.

When to stop cooling

This is the step most owners miss. Heat stroke can be fatal; so can over-cooling, particularly in dogs whose temperature regulation is already compromised. If you have a rectal thermometer and the animal will tolerate it, stop active cooling when their core temperature reaches around 39.4°C — about 103°F. Anything below that and you risk an undershoot in the other direction.

If you do not have a thermometer, the indicators are: the panting starts to slow and deepen, the dog's posture relaxes, they begin to look at you again rather than past you, and the tongue narrows and pulls back. At that point, stop active cooling, keep them in shade, keep airflow on, and take them to the vet.

What not to do

Three things make a bad situation worse. We have seen all of them, in this country, on emergency call-outs.

Do not pour ice water over the dog or wrap them in ice. As above — vasoconstriction stops the cooling and can kill an animal that would otherwise have lived.

Do not force water into the dog's mouth. A dog in heat stroke can have an impaired swallow reflex and will aspirate the water into their lungs, causing aspiration pneumonia on top of the heat injury. Offer water in a shallow bowl; do not pour.

Do not put a wet towel over the dog and leave it. Within a minute or two, the towel has absorbed body heat and is now an insulating warm blanket. If towels are used at all, they must be re-wetted every minute or two in cool water, and lifted off between applications to allow airflow.

There is a fourth thing not to do that is so common we list it here too: do not load the dog into a hot car to drive to the vet without first cooling them at home. If your car has not been air-conditioning for the last fifteen minutes, you are taking them from a hot environment into a hotter one. Cool them where you are, get the AC running with windows cracked, and only then put them in.

When to phone the vet

Immediately. Not after the cooling. Not when you have decided how bad it is. At the same time as you start the cooling, with the phone on speaker and the other hand on the dog.

The reason is partly the obvious one — they will be able to advise — and partly that a vet expecting a heat stroke case can have the IV fluids, oxygen and cooling equipment ready when you arrive. A heat stroke case that goes straight into active treatment at the surgery has a better prognosis than one that waits at reception. Tell them you are coming, tell them what you are seeing, and ask whether to come now or after some cooling at home. The answer will almost always be: now.

If it is out of hours, phone the emergency line. Do not wait until morning. Heat stroke is not a wait-and-see condition.

The thing many owners do not realise

An animal who appears to recover from a heat stroke is not necessarily out of danger. Heat injury causes systemic damage that often does not present for six to twelve hours. The organs most commonly affected are the kidneys, the liver, the gut lining and the clotting system. Acute kidney injury, disseminated intravascular coagulation, and gut bacterial translocation are all well-documented sequelae of canine heat stroke, and any of them can be fatal in the days following an event that looked, at the time, like a near miss.

This is why every heat-stroke case, however quickly the dog "seems fine again", needs a same-day vet visit. Bloods, fluids and a 24- to 48-hour period of close observation are the standard of care. The owners we see again, two days later, in a worse condition than the original event, are the ones who skipped this step because the dog appeared recovered.

The horse paragraph

Horses overheat by a different mechanism — primarily sweat, supplemented by the very large surface area through which they radiate. A horse in heat distress will be flank-breathing rather than nostril-breathing, may be unsteady, may stop sweating altogether (true anhidrosis is rare but real; partial anhidrosis is common), and will often refuse food and water.

The first aid is the same in principle: cool water over the neck, chest, belly and inside legs, scraping water off between applications, airflow if possible, shade always. The old idea that cold water on a hot horse causes muscle cramps — which kept generations of grooms hosing horses with tepid water — is not supported by the research done in racing and eventing over the last two decades. Cooling a horse fast, with cool water, repeatedly, is the right thing in a heat emergency. Call the vet for any horse you are actively cooling. Heat exhaustion in horses can progress quickly to dehydration colic, which is a separate emergency on top of the heat one.

The day after

Two things, the day after.

First, if your animal had any episode at all this week — even a small one, even one that resolved with five minutes in the shade — book a vet appointment. Bloods are cheap. Reassurance is worth a lot. Liver and kidney damage caught on day two is treatable; the same damage caught on day four often is not.

Second, take the lesson. Almost every heat case we see is on a routine the owner used to run safely and was running again this week because nothing felt different. The single thing that changed was the weather. Next year, when the first warm week of the year arrives — and warmer summers are now the rule rather than the exception in this country — the real work is the one done in March: planning the early-morning walks, knowing which days are car-free days, having the paddling pool ready, knowing your own dog's ceiling.

The piece on Monday was about the window in which you can still intervene. The piece on Tuesday was about not arriving at that window at all. This one is for the day you read both, and then misjudged it anyway. It happens. Owners are not always at fault for it. What matters today is the next thirty minutes, the day after, and the next year.

— Rene