Heatstroke in dogs and cats: signs, first aid and prevention

A 30 °C afternoon on the coast or in a Brussels top-floor flat: every summer, Belgian vets see dogs and cats in distress because of the heat. Heatstroke is not just "feeling tired": it is a life-threatening emergency that develops in a matter of tens of minutes. Here is how to recognise it, what to do and in which order, and above all how to avoid it.

Why heat is so dangerous for them

A dog barely sweats: it sheds heat by panting and through its paw pads. A cat licks itself to cool down and looks for shade. As soon as the air is as warm as their body, these mechanisms are no longer enough and core temperature climbs.

• The normal body temperature of a dog or cat is around 38 to 39 °C.
• Above 40 °C we talk about hyperthermia: that is the alarm threshold.
• FECAVA, the federation of European companion animal vets, points out that brain damage can occur from a core temperature of 41 °C and that mortality in confirmed heatstroke is around 50 %.

The longer the temperature stays high, the more the kidneys, liver and blood clotting suffer.

The signs that should alert you

In dogs, the first signs are often mistaken for tiredness:

• intense panting that does not settle at rest, tongue hanging far out, neck stretched;
• bright red gums and tongue, then pale or bluish in severe cases;
• heavy drooling, restlessness followed by lethargy;
• vomiting or diarrhoea, sometimes bloody;
• staggering gait, trembling, then collapse.

In cats it is more subtle: they hide, lie flat, breathe fast. A cat breathing with its mouth open is never "normal". If digestive upsets dominate, see our digestive warning signs, but during a heatwave think heat first.

Emergency steps, in order

1. Get your pet out of the heat. Shade, a cool room, a tiled floor. Stop all exertion.
2. Cool gradually. Wet the belly, inner thighs, paws and neck with cool, never iced, water: very cold water constricts the skin's blood vessels and traps heat inside, as the Flemish and Brussels animal welfare services point out. No ice cubes. A fan speeds up evaporation; if you lay damp cloths on your pet, change them often.
3. Offer small amounts of water at room temperature, never forcing a drowsy animal.
4. Call the vet without delay, even if your pet seems to be improving: internal complications can appear in the following hours. In the evening, at weekends or on public holidays, contact the on-call vet in your area; our guide explains how the veterinary on-call service works in Belgium.
5. Keep cooling during the journey, windows open or air conditioning on.

In an emergency, nobody can ever find the exact weight or the current treatments. The free Zoolinko health record lets you open a 72-hour emergency access for the on-call vet, who immediately sees your pet's file, linked to its microchip.

The car: a few minutes are enough

The most avoidable situation. The University of Veterinary Medicine Vienna published these measurements for a closed, parked car:

The rise is steepest in the first fifteen minutes. A slightly open window changes almost nothing, and Brussels Environment reports that the cabin can reach 80 °C in a heatwave. Even at 20 °C outside, a dog shut in a car is in danger after half an hour. In warm weather, your pet never stays alone in the car, not even "two minutes" for an errand.

What Belgian law says

Animal welfare is a regional competence, and the rules differ.

• In Wallonia, the Walloon Animal Welfare Code is explicit: leaving an animal shut in a vehicle "in such a way that ambient conditions could endanger the animal's life" is a third-category offence (article D.105, § 2, 36°). It becomes a second-category offence if the animal dies or is left permanently disabled.
• In Flanders and Brussels, as far as we know there is no equally specific article, but the legislation requires owners to provide conditions suited to their animal's needs, and the police do fine owners of dogs left in overheated cars. Dierenwelzijn Vlaanderen reminds everyone every summer never to leave an animal alone in a car, even briefly.

If you see a dog in distress in a vehicle, call the police on 101 rather than breaking a window yourself.

Prevention: walks, home, vulnerable pets

• Walk early in the morning or late in the evening. Between 12:00 and 16:00, asphalt can reach 60 °C and burn paw pads. Place the back of your hand on the ground for five seconds: too hot for you means too hot for your dog. Choose grass and shade, and check for ticks when you get home.
• No sport. Cycling, ball throwing, canicross: postpone to a cooler day. Many heatstrokes happen during exercise.
• At home: several bowls of fresh water, an accessible tiled floor or cooling mat, shutters closed on the sunny side, and an eye on cats on glazed balconies.
• Take extra care with the most vulnerable: brachycephalic breeds (bulldog, pug, boxer, Persian), older cats and dogs, overweight animals, heart patients or thick-coated pets. In them, the signs appear faster.
• In spring, forest walks also expose pets to processionary caterpillars: another seasonal emergency, same reflexes.