Emergency — phone the vet now Start cooling within 5 minutes

Dog suffering heat stroke or overheating

Move the dog to shade and start cooling with cool (not ice-cold) water on the belly and groin while someone phones the emergency vet.

Dog

Recognise the signs

Heavy, frantic panting that does not slow when at rest
Bright red or very dark gums
Excessive drooling, often thick and ropy
Wobbliness, glassy stare, confusion
Vomiting or diarrhoea, sometimes with blood
Collapse or seizure
Body temperature above 40°C (normal is 38.3–39.2°C)

First aid steps

Move the dog out of the heat into shade or air-conditioning.
Pour or sponge cool (not ice-cold) water over the belly, armpits, groin and paws.
Aim a fan at the dog if possible — evaporation is the main cooling mechanism.
Offer small amounts of cool water to drink if conscious and willing.
Phone the emergency vet while cooling — do not delay cooling to make the call.

Do NOT

Do not use ice or ice-cold water — peripheral vessels constrict and slow internal cooling.
Do not submerge the dog fully in a bath or pond — risk of inhalation if collapsing.
Do not force water down the throat of an unconscious dog.
Do not assume recovery once the dog seems better — internal organ damage can present 24–72 hours later.

While transporting to the vet

Keep windows open or AC on full.
Drape damp towels over the dog and keep them damp — replace if they warm up.
Do not cover the dog with wet blankets that trap heat — they must be loose and evaporating.

When to phone the vet immediately

Collapse, seizure, or unresponsiveness
Bloody vomit or diarrhoea
Gums that stay bright red, purple or pale despite cooling
Temperature still above 39.5°C after 10 minutes of cooling

Common causes

Exercise on a warm day, especially walks after 9am or before 6pm in summer
Trapped in a car (even with windows cracked, even at 22°C)
Confined in a hot conservatory, garden without shade, or boot of a car
Brachycephalic breeds in mild heat
Excitement and overexertion at events, beaches, or training

What the vet will need to know

How long the dog was exposed to heat
When signs started and how they have changed
Current temperature if you can take one (rectal)
Whether the dog has vomited, had diarrhoea, or collapsed
Breed, age, weight, and any heart or breathing conditions

Aftercare

All heat stroke cases need vet review even if they appear recovered — DIC and kidney injury can develop late.
Hospitalisation with IV fluids for 24–48 hours is common in moderate-to-severe cases.
Repeat blood tests at 24 and 72 hours to check kidneys and clotting.
Strict rest at home for several days; no exercise on warm days for 2 weeks minimum.

Prevention

Walk early morning or late evening in summer.
Use the 5-second pavement test — if it is too hot for the back of your hand, it is too hot for paws.
Never leave a dog in a parked car, even briefly, even with windows open.
Provide constant access to shade and water in the garden.
Carry a collapsible bowl and water bottle on every walk.

Breed-specific notes

Highest risk: Bulldogs, French Bulldogs, Pugs, Boxers, Shih Tzus and other brachycephalic breeds.
Also high risk: very young, elderly, overweight, or thick-coated dogs (Newfoundland, Husky, Saint Bernard).

Frequently asked questions

What temperature is too hot for dog walks?

There is no strict cut-off, but UK guidance from Vets Now and Blue Cross suggests caution above 20°C and avoidance of strenuous exercise above 24°C, lower for brachycephalic breeds. Humidity matters as much as temperature.

Can dogs really die in cars at mild temperatures?

Yes. At 22°C outside, a parked car interior can hit 47°C within an hour. Dogs cool only through panting and paw pads — they cannot survive in a hot car for long.

My dog seems fine after cooling down — do I still need a vet?

Yes. Heat stroke can cause delayed kidney injury, gut damage and clotting problems that appear up to 72 hours later. Vet review and bloods catch these early.