Cold or lukewarm water to cool a dog down?

Cool water, the coolest you have to hand: tap water is perfect. Avoid lukewarm water, which slows cooling, and above all ice-cold water or ice baths, which tighten the blood vessels and hold the heat in (Carter & Hall 2024).

Heatstroke in dogs

Health & preventionPart of · Health & prevention

Heatstroke in dogs

Q: What should you do if your dog has heatstroke?

Cool first, transport second. Move them into the shade, soak them with cool water (never ice-cold), add some moving air, then head straight to the vet, cooling them along the way. Don't waste time: it's the delay in cooling that puts them in danger.

Q: How can you recognise heatstroke in a dog?

Heavy panting that won't settle, bright red gums, thick drool, then staggering, vomiting or lethargy. Go by the signs , not the thermometer: this isn't a fever. At the first signs, start cooling and call the vet.

Q: How can you prevent heatstroke in a dog?

Walk early in the morning and late in the evening, never leave them alone in the car, keep shade and cool water freely available, and ease off the exercise when it's hot. The ground test (the back of your hand on the tarmac for 5 to 7 seconds) also spares their pads from burns.

Q: Should you see a vet if your dog seems to have recovered from heatstroke?

Yes, always. The body can deteriorate hours or even days later, through damage to the kidneys, liver or clotting (Bruchim et al. 2017). A consultation is exactly what picks up this damage before it shows, even if your dog looks fine.

Q: Which dogs are most at risk of heatstroke?

Flat-faced breeds (French Bulldog, Pug, Boxer) pant poorly and have roughly twice the risk (Hall et al. 2020). Add to that large and sporty dogs, and dogs that are overweight, very young or elderly. For them, ‘hot weather’ precautions are the rule, not the exception.

Q: At what temperature should you stop walking your dog?

There's no magic threshold: humidity, breed, age and how hard the exercise is all matter as much as the thermometer. The risk climbs around 25°C, sooner for vulnerable dogs. Think in terms of the signs and the ground test, not a fixed number.

8 min read

In hot weather, a dog who pants non-stop, drools thickly, staggers or keeps seeking shade may have heatstroke. The reflex that saves lives: move him into the shade, soak him with cool water and head to the vet, carrying on cooling him on the way.

What to do, in order: cool him first

Cool first, travel second: it is the delay in cooling that puts his life at risk, not the time spent soaking him before you set off.

Get him out of the heat

Stop the activity straight away, move him into the shade, somewhere cool, where the air moves.

Soak him with cool water

Soak him generously all over, paying special attention to the neck, the belly and the inner thighs. Use the coolest water you have to hand: tap water is perfect.

Add moving air

Point a fan at him, open the windows wide, or drive with the car windows down. On wet fur, moving air carries the heat away far faster than water alone.

Offer water, never force it

Offer him small sips of cool water if he is fully alert and drinks on his own. Otherwise never force him: it could go down the wrong way.

Get to the vet, cooling him on the way

Keep cooling him for the whole journey, even if he seems to be picking up, and ring the practice to say you are on your way.

The mistakes that make it worse

Leaving him in the sun or in the car while you get organised: as long as he stays at the heat source, his temperature keeps climbing. Get him out of the heat first, before you even look for water.
Laying a wet towel over his back: it traps the heat underneath instead of letting it escape. If a towel is all you have, slide it under him instead, and re-wet it often.
Forcing him to drink: it could go down the wrong way. Offer him water, but never force it.
Giving him a human painkiller or fever medicine (paracetamol, ibuprofen, aspirin): designed for the weight of an adult human, it can poison him, and heatstroke is not a fever to bring down anyway.
Waiting for him to "perk up" before cooling him: it is the delay in cooling that kills.
Putting ice or an ice pack straight onto his skin: cold that harsh closes the vessels under the skin and slows the heat escaping. Cool or cold water, yes; ice placed directly on him, no.
Plunging an unconscious dog into water to cool him: he could drown. If he is no longer responding, pour the water over him and add moving air, but never immerse him.

Spotting the signs, from mild to serious

Trust what you see, not a thermometer: heatstroke is not a fever, and a seriously affected dog can perfectly well have a normal temperature, as a 2021 veterinary study confirmed. Act from the very first signs.

First signs (cool him now)

Heavy, fast panting that does not settle
Bright red gums and tongue
Thick, stringy drool
Seeking shade and water, slowing down

It is getting worse

Staggering, unsteady walk
Vomiting or diarrhoea (especially if bloody)
He stays lying down without reacting, or seems disorientated

Life-threatening emergency

Collapse or loss of consciousness
Seizures, trembling
Pale, grey or brick-red gums

Staggering walk, trembling, seizures, collapse, or pale or grey gums: this is a life-threatening emergency, every minute counts.

Do this right now

Start cooling him with cool water straight away, and keep going during the journey
Ring the vet or an emergency veterinary centre to say you are on your way
Don't stop to look for a thermometer: act on the signs

Call your vetor an animal poison control centre: without delay.

The assistant never replaces a vet. When in doubt, call.

Preventing heatstroke

Some dogs cope far less well with heat: flat-faced breeds (French Bulldog, Pug, Boxer) pant poorly, and a large veterinary study of more than 900,000 dogs measures a markedly higher risk for them, up to three times higher depending on the situation. Add to that big-framed dogs and sporty dogs who push past their limits, dogs who are overweight, very young or elderly. For them, hot-weather precautions are the rule, not the exception.

Exercise in hot weather is the number one trigger: that is where most of the prevention is won.

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Hall et al. — Dogs Don't Die Just in Hot Cars: risk factors for heatstroke (VetCompass, 905,543 dogs) (2020)
Hall et al. — Canine heatstroke: mortality by clinical stage, and dropping the 41 °C threshold as a diagnostic criterion (2021)
Carter & Hall — Cooling methods: cold water is safe and faster, tepid water delays cooling (2024)
Bruchim et al. — Heat stroke in dogs: clinical review and delayed organ damage (24 to 48 hours, sometimes 3 to 5 days) (2017)
Royal Veterinary College / Vet-COT — "Cool first, transport second": cool the dog before you move him

Going further

guideThe first aid kit for your dogThe kit to put together before summer: everything you need to react fast if heatstroke strikes.Read the guide guideSpotting a life-threatening emergency in your dogTo learn to tell a heatstroke that passes from an emergency that cannot wait.Read the guide guideFever, cough, low energy: when to call the vetFever and listlessness can follow heatstroke: this guide helps you know when to see the vet.Read the guide guideDog vomiting and diarrhoea: what to do and when to see a vetVomiting or diarrhoea after a serious overheating episode: the right reflexes and the threshold that should worry you.Read the guide guideCaring for your dog's paw padsBurning tarmac damages the pads as much as heat exhausts the body: how to protect his paws in summer.Read the guide guideA Dog That Trembles: Understanding and RespondingA dog trembling after overheating is worrying: here is how to understand it and respond calmly.Read the guide

Frequently asked questions

What should you do if your dog has heatstroke?

Cool first, travel second. Move him into the shade, soak him generously with cool water, add moving air, then head to the vet while carrying on cooling him on the way. Don't lose time: it is the delay in cooling that puts his life at risk.

How can you recognise heatstroke in a dog?

Heavy panting that does not settle, bright red gums, thick drool, then staggering, vomiting or listlessness. Trust the signs, not the thermometer: this is not a fever. From the very first signs, cool him down and ring the vet.

How can you prevent heatstroke in a dog?

Walks early in the morning and late in the evening, never alone in the car, shade and cool water as much as he wants, and ease off on exercise when it is hot. The ground test (the back of your hand on the tarmac for 5 to 7 seconds) also spares him burnt pads.

Should you see a vet if your dog seems to have recovered from heatstroke?

Yes, always. In the hours or days that follow, the kidneys, the liver or the blood's clotting can deteriorate: a 2017 veterinary review shows this. That is exactly what the consultation is for, picking up damage that is not visible yet, even if your dog seems fine.

Which dogs are most at risk of heatstroke?

Flat-faced breeds (French Bulldog, Pug, Boxer) pant poorly: a large veterinary study of more than 900,000 dogs measures a markedly higher risk for them, up to three times higher depending on the situation. Add to that big-framed and sporty dogs, dogs who are overweight, very young or elderly. For them, hot-weather precautions are the rule, not the exception.

Cold or tepid water to cool a dog down?

The coldest water you have to hand: contrary to a widespread belief, cold tap water is safe for a conscious dog, and a 2024 veterinary study confirms it cools him faster than tepid water. Pour it over him, and never immerse him if he is no longer responding. What matters most is acting fast, with moving air on top: it is the speed of cooling that counts, not caution about the temperature.

At what temperature should you stop walking your dog?

There is no magic threshold: humidity, breed, age and how hard he is working count just as much as the thermometer. The risk rises from around 25 °C, earlier for fragile dogs. Think in terms of signs and the ground test, not a rigid number.

Updated on July 11, 2026Sources

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