Heatstroke in Dogs: The Signs, and What to Do First

Heatstroke in dogs moves faster than almost anything else you will deal with as an owner. It is also one of the few emergencies where what you do in the first few minutes, before you reach a vet, genuinely changes the outcome. This is worth reading before you need it.

What heatstroke actually is

A dog's normal body temperature sits a little above ours, around 38 to 39 degrees. Heatstroke is what happens when they cannot shed heat as fast as they are making or absorbing it, and their core temperature climbs past the point where the body can cope. Organs begin to be affected. It does not need a heatwave — a hot car, a midday walk, or an excited dog playing too long in the sun will do it.

The signs, roughly in the order they appear

• Heavy, frantic panting that does not settle when they stop moving.
• Thick, ropey drool, noticeably more than normal.
• Bright red gums and tongue, or in later stages unusually pale or grey ones.
• Restlessness, pacing, an inability to get comfortable anywhere.
• Wobbliness, stumbling, or legs that will not quite do as they are told.
• Vomiting or diarrhoea, sometimes with blood.
• Glazed eyes, confusion, not responding to their name.
• Collapse, seizures, or unconsciousness.

The first three are your warning. Everything from wobbliness down is an emergency already in progress.

What to do first

The order matters, and cooling comes before travelling.

1. Stop everything and get them out of the heat. Shade, indoors, air conditioning, anywhere cooler.
2. Start cooling them immediately. Pour or hose cool water over the whole body, and keep going. Concentrate on the belly, the armpits, the groin and the inside of the legs, where blood vessels run close to the surface. Do not wrap them in a wet towel and leave it — a towel that sits there traps heat rather than releasing it.
3. Get air moving over the wet coat. A fan, an open car window, even someone waving a magazine. Evaporation is what carries the heat away, and water without airflow does half the job.
4. Offer small amounts of cool water to drink if they are conscious and able to. Do not force it, and do not let them gulp a huge volume at once.
5. Ring your vet, and go. Tell them you are on your way and what has happened. Keep cooling in the car with the windows down or the air conditioning on the body.

The mistakes that make it worse

• Waiting to see if they improve. Minutes count, and a dog that looks slightly better can still be in serious trouble internally.
• Driving without cooling first. Even a few minutes of cooling before you leave is worth having.
• Covering them in wet towels and leaving them on. Once a towel warms up it is insulation.
• Not going to the vet because they seem to have recovered. This is the big one. Heatstroke can cause internal damage — to the kidneys, the gut and the clotting system — that shows up hours later, long after the dog looks fine. A dog that has genuinely overheated needs to be seen, even if they are up and wagging by the time you would have left.

The dogs most at risk

Flat-faced breeds are in a category of their own, because panting is the primary cooling system and a shortened airway makes it far less efficient. Pugs, French and English bulldogs and boxers can get into difficulty on a day other dogs handle comfortably. After them: overweight dogs, thick-coated breeds, older dogs, very young dogs, and any dog with existing heart or airway problems.

The one that is not worth risking

A parked car on a warm day reaches dangerous temperatures within minutes, and a cracked window changes that far less than people expect. There is no version of this that is safe, including a short trip into the shops on a mild day.

Prevention, briefly

Walk at the ends of the day. Test the footpath with the back of your hand before you set out. Keep water available in more than one spot. Give them somewhere genuinely cool to lie so they are not starting the hot part of the day already warm. And on the worst days, accept that a sniff around the garden is a perfectly good substitute for a walk.

This is general information, not veterinary advice. If you think your dog is overheating, ring your vet — they would far rather hear from you early than late.