Heatstroke in Dogs: Warning Signs, First Aid and How to Prevent It

Dogs can't sweat the way people do. They cool down mainly by panting and through their paw pads, and when the air is too hot or humid, that isn't enough. Body temperature climbs, organs begin to fail, and a dog can go from happily trotting along to collapsing in a matter of minutes.

Heatstroke is an emergency, but it's also one of the most preventable ones. This guide explains the signs, the first aid that buys you time, and the habits that keep your dog safe.

What Heatstroke Is

A dog's normal body temperature is roughly 38 to 39.2°C (about 100.5 to 102.5°F). Heatstroke occurs when it rises above about 40°C (104°F) and the body can no longer cool itself. At 41°C (106°F) and above, cells and organs start to be damaged, and without treatment it can be fatal.

It isn't only a summer problem. Hot cars, humid rooms, enthusiastic play in mild weather, and poor ventilation can all cause it.

Warning Signs

Early signs may look like normal panting, so know what to watch for.

Early

• Heavy, noisy panting that doesn't settle
• Drooling more than usual
• Bright red tongue and gums
• Restlessness, searching for shade or cool floors
• Reluctance to keep moving

Serious

• Vomiting or diarrhoea, possibly with blood
• Weakness, stumbling or wobbliness
• Pale, grey or blue gums
• Rapid heartbeat
• Glazed eyes, confusion
• Collapse, seizures or loss of consciousness

If you see these signs, act immediately. Don't wait to see if they improve.

What to Do Straight Away

1. Move your dog out of the heat into shade or air-conditioning
2. Call your vet or nearest emergency clinic while you cool your dog, and tell them you're coming. Heatstroke needs professional treatment even if your dog seems to recover
3. Cool with water. Pour cool (not ice-cold) water over the body, particularly the belly, groin, armpits and paws. Wet the ears and neck too
4. Use airflow. A fan or air-conditioned car speeds up evaporation
5. Offer small sips of cool water if your dog is alert. Don't force it
6. Stop cooling once panting eases and the dog feels comfortably warm rather than hot, or when your vet tells you to. Over-cooling is also harmful
7. Get to the vet. Travel with the air-conditioning on and the windows open if you can

Things not to do:

• Don't use ice-cold water or ice baths, which can narrow blood vessels and trap heat
• Don't wrap your dog in a wet towel, which can act like a blanket
• Don't give a dog who is vomiting or semi-conscious anything to drink
• Don't assume they're fine because they seem better. Heatstroke can cause internal damage that appears hours or days later

Which Dogs Are Most at Risk

• Flat-faced breeds such as pugs, bulldogs, French bulldogs and Boston terriers
• Puppies and older dogs
• Overweight dogs
• Thick or double-coated breeds (although never shave a dog down to the skin without advice)
• Dogs with heart or lung disease, or laryngeal paralysis
• Dark-coated dogs in the sun
• Dogs not used to heat, such as after travel or a sudden heatwave
• Dogs with a history of heatstroke

Even a dog who handles warm weather well can overheat when exercising hard.

The Parked Car Danger

Never leave a dog in a parked car, not even for a few minutes, and not even with the windows open or in the shade. On a mild day, the inside of a car can reach dangerous temperatures within ten minutes. If you see a dog in distress in a car, call the local emergency services or police.

Preventing Heatstroke

Exercise

• Walk early in the morning or late in the evening in hot weather
• Test the pavement with the back of your hand for five seconds. If it's too hot for you, it's too hot for paws
• Keep walks short, choose shade and carry water
• Skip fetch and running in the heat of the day

At home

• Provide plenty of fresh water and shade, indoors and out
• Use fans, cooling mats or damp towels for lying on
• Keep the house ventilated or air-conditioned
• Never leave a dog in a conservatory, greenhouse or unshaded garden
• Freeze treats such as bone broth ice cubes (check ingredients are dog-safe)

Grooming

• Brush out loose undercoat regularly
• If you trim, leave a decent length of coat, since it also provides insulation. Talk to a groomer about the best clip for your breed

Travel

• Use car sunshades and air-conditioning
• Take breaks and have water ready
• Don't leave your dog in the car, even briefly

Small dogs can overheat quickly, as can toy breeds who are very active. Our guide on how much exercise a Yorkie needs includes tips on adjusting exercise for the weather.

After Heatstroke

Your vet may keep your dog for monitoring, give fluids and run blood tests to check organs. Some dogs recover fully, but others have lasting kidney, liver or brain damage. A dog who has had heatstroke is more susceptible to it in future, so take extra care.

Frequently Asked Questions (FAQ)

How quickly can heatstroke develop?

Very quickly. In a hot car, a dog can be in trouble in minutes. Exercising in warm, humid weather can cause it within about half an hour.

Is heavy panting always heatstroke?

No, dogs pant when excited, nervous, or after exercise. It's the combination of heavy panting that doesn't settle, along with other signs such as drooling, red gums or weakness, that signals trouble.

Can I give my dog a cold bath?

Use cool or lukewarm water, not ice-cold. Pour or sponge it on rather than submerging a weak dog.

Do I still need the vet if my dog recovers?

Yes. Internal damage can develop afterwards, so a check-up is important.

Should I shave my dog in summer?

Usually not. Coats insulate against heat as well as cold. Ask a groomer or vet about trimming instead.

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Disclaimer: This article is for general information and does not replace professional veterinary advice. If you suspect heatstroke, treat it as an emergency and contact a vet immediately.