Heatstroke in Dogs: Cool First, Then Travel to the Vet

Every instinct tells you to put the dog in the car and drive. With heatstroke that instinct kills, because the heat is doing the damage while you drive.

It is almost always an ordinary walk. Not a heatwave, not a dog shut in a car, just a warm afternoon and a dog that would not think to stop.

Heatstroke is the fastest killer in this guide, and it is the one where what you do in the first few minutes, before a vet is anywhere near your dog, decides the outcome. There is one rule and it runs against instinct: cool the dog first, then travel.

Why cooling comes before driving

A dog cannot sweat. It sheds heat mainly by panting, which is far less efficient than it needs to be on a hot day or during exercise. Once the body temperature climbs past what it can shed, the heat itself starts injuring organs, and it keeps doing so every minute it stays high.

So a twenty-minute drive to the vet with an uncooled dog is twenty more minutes of damage. Cooling at the scene, and continuing to cool in the car, is not a delay to treatment. It is the treatment, until you arrive.

What to do

1. Ring your vet to say you are coming and describe what is happening.
2. Stop the heat going in. End the walk, stop all exercise, and get the dog out of the sun, the car or the hot room into shade.
3. Pour cool water over the body, avoiding the head. For most dogs you can lower the body into water while keeping the head well clear.
4. Get air moving. A fan, an open window, a breeze. Evaporation is doing a lot of the work.
5. Drive to the vet with the car cool, and keep cooling on the way.

Some dogs need gentler handling. Do not submerge a dog that is unconscious, elderly, or has known health problems. Spray or pour room-temperature water over those dogs instead.

What not to do

Never use ice or iced water. This is the mistake that feels most obviously right and is most obviously wrong. Extreme cold clamps down the blood vessels in the skin and sets off shivering, and both of those slow heat loss rather than speeding it. Cool tap water is what you want, not the freezer.

Do not drape wet towels over the dog. A towel lying over the body traps heat underneath it. Wet towels can go under the dog and be re-wetted often, but never over the top.

Do not pour water into the mouth of a dog that is dazed, unsteady or unable to swallow properly. It goes into the lungs.

Do not delay cooling in order to set off sooner. Start where you are.

What to look for

Early, and the point at which you act:

• Heavy panting, noisy or faster breathing than usual
• Bright red gums and tongue
• Thick, sticky drool
• A fast heart rate
• Weakness, stumbling, trouble standing
• Confusion or disorientation
• Vomiting or diarrhoea

Late, and the point at which you move faster, not slower:

• Pale, grey or blue-tinged gums
• Collapse
• Seizures
• Unresponsiveness

That colour change matters enormously. Red gums say a dog is overheating. Pale or grey gums say it is going into shock, and it is a mistake to read the loss of the bright red as improvement.

If the dog is not breathing or has no heartbeat, this is no longer heatstroke first aid. Start CPR and get moving.

Who is at risk, and the walk that causes it

Exercise is the single biggest trigger, which is why so many cases start as a normal walk rather than a dog left somewhere hot. Flat-faced breeds like Bulldogs, Pugs and Boxers overheat fastest because their airways are already working harder at rest. Overweight dogs, older dogs, thick-coated breeds and dogs with heart or airway conditions are all less able to cope.

On warm days, walk early or late and skip the middle of the day entirely. Test the pavement with the back of your hand before you set off. Carry water. And treat heavy, distressed panting as a signal to stop, find shade and cool down, rather than something to push through to get home.

Never leave a dog in a parked car, not even briefly, and not with the windows cracked.

Sources

This article was written using guidance from RSPCA, the Royal Society for the Prevention of Cruelty to Animals, the UK's oldest animal welfare charity; PDSA, the UK's largest veterinary charity, whose Pet Health Hub is written by its own vets and nurses; and AVMA, the American Veterinary Medical Association, the professional body representing US veterinarians. This guidance is for general information and does not replace a consultation with your own veterinarian. In an emergency, always contact a vet. Read [how we write our health guidance](https://rochsociety.com/how-we-write-our-health-guidance/). Last reviewed July 2026.