Dog Heatstroke in the UK: Warning Signs, First Aid, and How to Prevent It

Most UK dog owners picture heatstroke as something that happens to a dog locked in a hot car. That is true, but it is not the main story.

Research from the Royal Veterinary College's VetCompass programme, which reviewed clinical records from over 900,000 UK dogs, found that exertion during ordinary walks and play is actually a more common trigger of heatstroke than being left in a vehicle. Knowing the real risk means knowing what to watch for on any warm day, not just the exceptionally hot ones.

UK dogs are at risk at lower temperatures than you might think

The same VetCompass programme analysed confirmed heat-related illness cases from UK veterinary practices, based on records from over 900,000 UK dogs under veterinary care in 2016, and found an event fatality rate of just over 14%.

A follow-up analysis of that dataset found a median outdoor temperature of just 16.9°C on the day a dog developed heatstroke, and that dogs unable to escape a heat source faced greater risk of severe disease than dogs that were simply exercising. That is a mild day by most standards, not a heatwave, and it is why a warm car, a sealed conservatory, or a garden with no shade can be more dangerous than a walk.

Which dogs are most vulnerable

VetCompass research analysing UK veterinary records identified breed, bodyweight, and age over two years as significant risk factors for a dog developing heat-related illness in the first place. A separate analysis looking specifically at cases that progressed to severe disease found a different picture: once a dog had heat-related illness, trigger, age, and bodyweight were the significant factors for severity, with breed no longer significant at that stage, while flat-faced skull shape was specifically linked to fatal outcomes.

The RSPCA adds that dogs with thick coats, very young puppies, senior dogs, and dogs with underlying respiratory conditions are also at increased risk, since panting is a dog's main way of regulating body temperature. If you own a French Bulldog, Pug, or another brachycephalic breed, or a senior or overweight dog of any breed, it is worth treating warm days with extra caution well before the weather feels like a heatwave to you.

Recognising the warning signs

Heatstroke can escalate quickly, so early recognition matters. The RSPCA lists collapse, confusion, vomiting and lethargy among the key warning signs, alongside heavy panting, drooling, and a rapid heart rate. Diarrhoea containing blood is a marker of a more severe case. If you see any combination of these signs, particularly in a dog that has been exercising, shut in a warm space, or is one of the higher-risk types above, treat it as an emergency rather than waiting to see if it passes.

What to do if you suspect heatstroke

The RSPCA's guidance is straightforward: cool first, transport second. That means acting immediately to lower your dog's temperature before you head to the vet, not instead of going to the vet. Pour or spray cool, not ice-cold, water over your dog's neck, stomach and thighs, avoiding the head, and use a fan or a breeze to maximise evaporative cooling.

Avoid covering your dog with a wet towel, since it can trap heat rather than release it, though a damp towel underneath them is fine. Offer small amounts of cool water to drink if your dog is able to. Once you have started cooling them down, get to a vet immediately, even if your dog seems to be improving, since organ damage from heatstroke can appear later.

Preventing heatstroke in the first place

Prevention is simpler than treatment and far kinder to your dog. The RSPCA recommends walking during the cooler parts of the day and avoiding exercise in the afternoon heat, never leaving a dog alone in a car, conservatory, or caravan, even with windows open. It is also worth checking pavement temperature with the back of your hand before a summer walk; if you cannot hold it there comfortably for five seconds, it is too hot for your dog's paws.

What your dog wears matters too. A heavy or tightly fitted collar can trap heat against the neck on a warm day, so many owners switch to something lighter for summer walks. If you are looking for a breathable alternative, our bandana collection is a popular choice for keeping a dog looking sharp without the bulk of a full collar in hot weather, while our lightweight collar collection still gives you a secure ID point for the lead.

Heatstroke is one of the more preventable emergencies in dog ownership, but only if you know the real risk factors rather than the popular image of it. Watch the temperature, watch your dog, and act fast if something seems off. It could make all the difference.