Heatstroke in dogs: what to do
In hot weather, a dog that pants non-stop, drools thickly, staggers or keeps seeking shade may be having a heatstroke. The reflex that saves lives: move them into the shade, wet them down with cool water (never ice-cold) and head straight to the vet, cooling them along the way.
What to do, in order: cool first
Cool first, transport second: it's the delay in cooling, not the stress, that puts life at risk.
Get them out of the heat
Stop any exertion straight away, move them into the shade, somewhere cool, in a draught of air.
Wet them down with cool water
Generously over the body, focusing on the neck, belly and inner thighs. The coolest water you have to hand, never ice-cold.
Add moving air
A fan or a draught speeds up evaporation a great deal, especially on a wet coat.
Offer water, but never force it
Small sips of cool water only if they are fully alert and drinking on their own (otherwise, there's a risk of it going down the wrong way).
Get to the vet, cooling along the way
Even if they seem to be improving, and let the clinic know you're on your way.
Spotting the signs, from mildest to most serious
Go by what you see, not by a thermometer: heatstroke isn't a fever, and a severely affected dog can show a normal temperature (Hall et al. 2021). Act at the very first signs.
First signs (cool them now)
- Heavy, rapid panting that won't settle
- Bright red gums and tongue
- Thick, stringy drool
- Seeking shade and water, slowing down
It's getting worse
- Staggering, unsteady gait
- Vomiting or diarrhoea (especially if bloody)
- Marked lethargy, disoriented dog
Life-threatening emergency
- Collapse or loss of consciousness
- Seizures, trembling
- Pale, grey or brick-red gums
Staggering gait, trembling, seizures, collapse or pale/grey gums: this is a life-threatening emergency, every minute counts.
Do this right now
- Start cooling with cool water straight away, and keep it up during the journey
- Call the vet or an emergency veterinary centre to warn them you're on your way
- Don't waste time looking for a thermometer: act on the signs
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) that pant poorly are around twice as likely to be affected (Hall et al. 2020), as are large builds and sporty dogs that push themselves beyond their limits, and dogs that are overweight, very young or elderly. For them, "hot weather" precautions are the rule, not the exception.
Exertion in hot weather is the leading trigger: that's where most of the prevention plays out.
0 / 5- 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, abandoning 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 h, sometimes 3 to 5 days) (2017)
- Royal Veterinary College / Vet-COT — "Cool first, transport second": cool before transporting
Frequently asked questions
What should you do if your dog has heatstroke?
Cool first, transport second. Move them into the shade, wet them down generously with cool water (never ice-cold), add moving air, then head to the vet, cooling them along the way. Don't waste time: it's the delay in cooling that puts them in danger.
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, cool them down and call 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 freely available, and ease off on exertion when it's hot. The ground test (the back of your hand on the tarmac for 5 to 7 seconds) also prevents burnt pads.
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). The consultation is exactly what picks up this hidden damage, even if your dog seems to be doing fine.
Cold or tepid water to cool a dog down?
Cool water, the coolest you have to hand: tap water is perfect. Avoid tepid water, which slows cooling, and above all ice-cold water or ice-cube baths, which tighten the blood vessels and hold heat in (Carter & Hall 2024).
Which dogs are most at risk of heatstroke?
Flat-faced breeds (French Bulldog, Pug, Boxer) pant poorly and are around twice as likely to be affected (Hall et al. 2020). Add to that large builds and sporty dogs, and dogs that are overweight, very young or elderly. For them, "hot weather" precautions are the rule, not the exception.
At what temperature should you stop walking your dog?
There's no magic threshold: humidity, breed, age and how hard the dog is working all matter as much as the thermometer. The risk rises around 25°C, earlier for fragile dogs. Reason in terms of signs and with the ground test, not a rigid number.
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