Heatstroke in Dogs: Recognise It, Cool It, Get Help

Heatstroke is a medical emergency, not a discomfort. A dog's body temperature rises faster than it can shed heat, and once the core temperature passes roughly 40°C, organs begin to fail. The difference between a full recovery and a fatality is usually measured in minutes, not hours.

Why dogs overheat so quickly

Dogs cool themselves mainly by panting and by a small amount of sweat through their paw pads. They cannot sweat through their skin the way humans do, which makes them far more vulnerable in heat and humidity.

Risk goes up sharply with:

• Flat-faced breeds — pugs, bulldogs, boxers, shih tzus
• Thick-coated and double-coated breeds
• Puppies, senior dogs, and overweight dogs
• Dogs with heart or breathing conditions
• Confinement in a car, even with windows cracked
• Exercise in the middle of the day
• High humidity, which makes panting far less effective

A car parked in the sun can reach dangerous temperatures within minutes, even on a mild day. Leaving a window open does not make it safe.

The early signs

Catch it here and most dogs recover fully:

• Heavy, rapid panting that does not settle
• Restlessness and pacing
• Excessive drooling, sometimes thick and sticky
• Bright red gums and tongue
• Warm ears and paws
• Reluctance to walk or lie down in shade

The emergency signs

These mean the dog needs a vet now:

• Staggering, weakness, or collapse
• Confusion, disorientation, or seizures
• Vomiting or diarrhoea, sometimes with blood
• Gums that turn pale, grey, or blue
• Laboured breathing, or a breathing pattern that sounds raspy
• Body temperature above 40°C measured rectally
• Unresponsiveness

What to do, in order

1. Move the dog out of the heat. Shade, indoors, air conditioning, or a fan. Do not wait for the dog to walk; carry a small dog.
2. Call the vet while you start cooling. Tell them you are coming and follow their instructions.
3. Apply cool — not ice-cold — water. Wet the dog thoroughly, especially the neck, armpits, groin, and belly, where blood vessels are close to the skin. Use a sponge, a cloth, or a gentle hose.
4. Increase airflow. A fan over the wet dog speeds evaporation, which is how cooling actually happens.
5. Offer small sips of water if the dog is conscious and swallowing normally. Do not force water into the mouth.
6. Transport immediately. Cooling on the way is fine, but do not delay the journey to finish cooling at home.

Why ice is the wrong instinct

Ice packs, ice baths, and near-freezing water cause blood vessels in the skin to constrict. That traps heat in the core instead of releasing it, and it can push the dog into shivering — which generates more heat. Cold water on the surface can also make a dog's temperature drop dangerously fast once cooling begins.

Use tap-cool or lukewarm water, keep air moving, and let the vet manage the core temperature.

What not to do

• Do not leave the dog alone to "cool down naturally".
• Do not cover the dog with wet towels and then leave them in place; towels trap heat once they warm up. Wet the coat and keep air moving instead.
• Do not give human medication, including aspirin or paracetamol.
• Do not pour water into the mouth of an unconscious dog.
• Do not assume the dog is fine because it is standing. Internal damage can appear hours later, which is why a vet check is recommended even after a mild episode.

After recovery

A dog that has had heatstroke is more vulnerable to it again. For the rest of that summer:

• Walk early morning and after sunset, never in peak heat
• Test the pavement with the back of your hand for five seconds — if it is too hot for you, it is too hot for paws
• Carry water on every walk
• Never leave a dog in a parked car, even briefly
• Keep flat-faced dogs indoors during heatwaves

Protecting street animals in a heatwave

Community dogs and cats face the same heat with fewer options. Simple, practical help:

• Place shallow bowls of clean water in shaded spots and refill them daily
• Put water out at dusk and dawn, when animals are most active
• Never move a dog that is resting in shade — that patch of shade may be the only cool spot it has
• Watch for dogs lying flat with heavy panting; that is a medical emergency, not laziness
• Avoid feeding heavy meals in peak heat

Frequently asked questions

What is a normal dog temperature? Roughly 38.0–39.2°C. Above 40°C with heat exposure is an emergency. Use a digital rectal thermometer; ear thermometers are unreliable in dogs.

How fast can heatstroke develop? In a hot car it can develop in under 15 minutes. During vigorous exercise in high humidity, it can develop in 20 to 30 minutes.

Can a dog survive heatstroke without a vet? Mild cases sometimes recover with cooling alone, but organ damage and clotting problems can develop hours later. A vet check is strongly recommended after any episode.

Is it safe to walk a dog at 35°C? No. Shift walks to early morning or late evening, keep them short, and choose grass or shaded routes over asphalt.