Heatstroke in dogs: signs, cooling and when to go to a vet

A dog's normal temperature is about 38.6 to 38.9 °C. The 2026 RECOVER first-aid guidelines for dogs and cats define heatstroke as a core temperature above 41 °C together with signs that the brain is affected, such as confusion, stumbling or collapse. Most owners have no way to take a dog's temperature on a walk, which is why the guidelines ask owners to learn the early signs and act on them, rather than wait for a number.

Dogs lose heat mainly by panting. When the air is hot and humid, or the dog is working hard, panting cannot keep up, and heat builds faster than the body can shed it. The longer a dog stays overheated, the more damage is done, and the RSPCA's short version of the first-aid rule is: cool first, transport second.

It is often fatal. About 1 in 7 dogs with heat-related illness died in UK vet-practice records, and in a hospital study about half of dogs with severe heatstroke died even with intensive treatment. A dog can seem to recover after cooling and still have damage that shows later, which is why every case needs a vet.

The 2026 RECOVER guidelines prefer cool running water over the body and belly, and show lowering the back half of the body into water as an option only in outdoor settings, keeping the face clear to avoid drowning. The RSPCA and a 2023 Royal Veterinary College study also allow lowering a conscious, healthy dog's body, never its head, into cool water if it is safe to do so.

The Merck Veterinary Manual's owner page says not to immerse the animal in cold water, and suggests cool water, ice packs or wet towels on the belly together with a fan. The RSPCA warns against laying damp towels over a hot dog's body, because they trap heat, though wet towels under the dog are fine if they are re-wetted often. Where the advice differs, use what every source agrees on: cool running water, the belly, moving air, nothing over the face, and a vet straight after.

IMD notes that high humidity and hot winds make a heat wave worse for people, and that warm nights stop the body recovering from the day's heat. Dogs, which cool mainly by panting, are in the same position: panting moves heat out as moisture, and that works less well when the air is already wet. On the coast IMD treats 37 °C as heat-wave territory, well below the 40 °C used for the plains.

That is why heatstroke is not only a north Indian May problem. In Mumbai, May nights average 27.0 °C, humidity stays around 81% on a July evening, and November is the city's hottest month by average high. In Delhi, June nights average 27.7 °C. A dog that has spent a hot night in a stuffy flat starts the morning walk already warm. On those days, keep walks short and slow, carry water, and stop at the first heavy panting.

Most heatstroke follows exercise, so the walk is where prevention starts: dawn and late-evening walks in the hot months, shorter and slower outings on humid days, water on every walk, and no fetch or running in the heat for flat-faced, heavy or older dogs. Never leave a dog in a parked car, even briefly. A dog that has had heatstroke once needs extra care, so ask your vet for a plan before the next summer.

Our summer guide covers the rest of the season in detail: IMD's heat-wave warnings, walk times and hot roads, water and shade, and keeping a flat cool through power cuts. Under the Prevention of Cruelty to Animals Act, 1960, anyone in charge of an animal must take reasonable care of its well-being, a duty the Animal Welfare Board of India cites in its hot-weather advisory.

When Petym opens in a city, a sitter will follow your dog's plan as you write it, including walk times, and log each walk as it happens; you will get a photo update every day of the booking. In the hot months, write the summer rules into the plan: the walk window, how long and how far, the coolest room, and whether your dog is flat-faced, old, heavy or has a breathing or heart problem.

Every Petym sitter completes pet first-aid training before the first booking and has a named 24-hour vet within reach. If your dog shows signs of heatstroke, the sitter will start cooling it on the spot, call you, and take it to the nearest 24-hour vet on the city's list. A free meet and greet before the first booking is the time to show the sitter the coolest room, where the water is kept, and your vet's number.