Heatstroke in dogs: what to do in the first few minutes

Key points

• Heatstroke is an emergency: cool your dog down and always take them to the vet, even if they seem to have recovered.
• Wet their whole body with cool tap water, not ice water, and get air moving; don't leave them wrapped in a wet towel.
• Flat-faced, overweight, older dogs, puppies and dogs with heart or breathing problems are at much higher risk.
• Never leave a dog in the car, not even for five minutes or with the window down.
• Don't give them any fever medicine: acetaminophen (paracetamol) and ibuprofen are toxic to dogs.

Heatstroke in dogs is a veterinary emergency: body temperature rises above 106 °F (41 °C) and starts damaging organs within minutes. What you do in the first few minutes matters a great deal, but it doesn't replace the vet, even if your dog seems to recover.

Dogs barely sweat; they cool down by panting, and when the air is hot and humid or they can't stop, that system can't keep up. It happens mostly in summer, but also on the first warm days of spring, in parked cars and on runs or bike rides at midday. Here's how to recognize it, what to do step by step on the way to the clinic, the most common mistakes and how to prevent it.

Symptoms: how to recognize heatstroke

Early signs

• Very heavy panting that doesn't settle when they stop and get into the shade.
• A wide tongue hanging out, and very red gums and tongue.
• Thick drool.
• Restlessness, looking for shade or a cool floor, refusing to keep walking.

Serious signs

• Weakness, staggering, lying down and not wanting to get up.
• Noisy or labored breathing, or panting that becomes weak.
• Vomiting or diarrhea, sometimes with blood.
• Pale, grayish or purple gums, or tiny red dots on the gums and skin.
• Disorientation, seizures or loss of consciousness.

A dog's normal rectal temperature is between 100.4 and 102.5 °F (38 and 39.2 °C). Above 104 °F (40 °C) at rest there's already a problem, and above 106 °F (41 °C) we're talking about heatstroke. If you're unsure, act as if it is: cooling down an overheated dog won't hurt them.

Which dogs are most at risk

• Flat-faced breeds: French and English Bulldogs, Pugs, Boxers, Shih Tzus, Cavalier King Charles Spaniels. They breathe and pant less efficiently; some have many times the risk of a long-nosed dog.
• Overweight dogs, older dogs and puppies.
• Dogs with heart or respiratory disease, such as laryngeal paralysis in older Labradors or tracheal collapse in small dogs.
• Dense or dark coats and Nordic breeds.
• Very active dogs that don't know when to stop, especially on the first hot days, before they've acclimatized.

And situations that put any dog at risk: a parked car (the temperature inside can rise by about 18 °F (10 °C) in ten minutes, even with the window down), running or cycling alongside you in the heat, beaches with no shade, patios and yards in full sun, a crate in the sun and fabric muzzles, which don't let them pant.

Common mistakes that make things worse

• Waiting at home to see if they recover. Even if they seem better, internal damage can show up hours later.
• Using ice or ice water. There's no need: cool tap water cools them more than enough, and with ice they're more likely to shiver, or you may overdo it and end up making them too cold.
• Leaving them wrapped in a wet towel. The towel warms up quickly and acts like a blanket. It's better to pour water directly on them and get air moving.
• Pouring water into their mouth or forcing them to drink if they're dazed: it can go into the lungs.
• Giving them fever medicine. It doesn't help, because it isn't a fever but built-up heat, and acetaminophen (paracetamol), ibuprofen and aspirin are toxic to dogs.
• Cooling without checking. Once they reach about 103 °F (39.5 °C), stop active cooling so you don't cause the opposite problem.
• Putting them in a pool or the sea if they're weak: they could drown. If you put them in water, make it shallow and hold their head out.

Why you must go to the vet even if they seem fine

Extreme heat damages the kidneys, liver, intestines, brain and blood clotting system. Some of that damage doesn't show until 24-72 hours later: a dog that seemed to have recovered can start having bloody diarrhea, bleeding or kidney failure. At the clinic they'll give IV fluids, run blood tests, give oxygen if needed and monitor your dog.

The chances of recovery are much higher if the dog arrives already cooled down. That's why the rule is cool first and transport after, or cool during transport, but always go.

How to prevent heatstroke

• In summer, walk early in the morning and late in the evening. Before you head out, press the back of your hand on the pavement for five seconds: if you can't hold it there, it burns. A paw pad balm helps with dryness, but it won't protect against a burn.
• Always provide cool water and shade, at home, on the patio and in the yard too. Bring water and a collapsible bowl on every walk.
• Never leave your dog in the car, not even for five minutes.
• No running or cycling in the heat or high humidity, especially on the first hot days.
• If your dog needs a muzzle, use a basket muzzle so they can pant and drink.
• Don't shave a double-coated dog down to the skin: their coat also insulates them from the sun. Brush often to remove dead undercoat.
• In flat-faced dogs, keep their weight in check and use a harness instead of a collar.
• A kiddie pool in the shade or a cooling mat helps at home, and a frozen treat like watermelon ice cream is a nice extra on hot days. But none of these is a treatment if there are already symptoms.

What you need

• Plenty of water (at least 1.5 liters, about 50 oz) and a collapsible bowl on every summer outing
• A spray bottle or a bottle to wet them with
• A digital thermometer and petroleum jelly
• A fan or a piece of cardboard to fan them
• Your vet clinic's number and a 24-hour emergency vet's number saved in your phone

Step by step

1. Get them out of the heat

   Stop any exercise and move your dog into the shade, somewhere cool or air-conditioned. Take off their muzzle and any clothing or harness that's tight.

2. Wet them with cool water

   Pour cool water from the tap, a hose or bottles all over their body, focusing on the neck, chest, belly, armpits, groin and paws. Keep wetting them continuously; if they're conscious and can stand, they can stand in shallow cool water with their head out.

3. Get air moving

   A fan, a piece of cardboard, the car windows or the air conditioning. Moving air evaporates the water, and that's what cools them most.

4. Call the clinic

   Call while someone else keeps cooling your dog: say you're coming in with a possible heatstroke so they're ready for you.

5. Offer water without forcing it

   If they're conscious and want to, let them drink small amounts. If they're dazed, don't pour water into their mouth.

6. Check their temperature

   If you have a thermometer, take their rectal temperature every five minutes. Once it reaches about 103 °F (39.5 °C), stop wetting them, but don't cover them up.

7. Go to the vet

   Always, even if they seem to have recovered. On the way, air conditioning on full and keep wetting them if they're still hot.

Frequently asked questions

How do I know if my dog has heatstroke?

Suspect heatstroke if your dog is panting very hard and doesn't calm down when they stop, has thick drool, very red tongue and gums, or is weak and wobbly. Vomiting, diarrhea, pale or purple gums, confusion or seizures mean it's serious. Cool them with cool water and take them to the vet right away.

Can I put cold water on my dog if they're overheated?

Yes, with cool tap water, all over the body, while getting air moving so it evaporates. There's no need for ice or ice water: cool water works very well, and with ice they're more likely to shiver or you may overdo it. If they have heatstroke symptoms, wet them and take them to the vet even if they improve.

What temperature is too hot to walk a dog?

There's no single number, because humidity, sun, the type of dog and the exercise all play a part. Above 77 °F (25 °C) with high humidity, flat-faced, older or overweight dogs are already at risk on a demanding walk. In summer, go out early and late in the evening, avoid hot pavement and adjust the exercise.

How long does it take a dog to recover from heatstroke?

It depends on how severe it was and how quickly they were cooled. A mild case treated in time usually recovers in one or two days, often with a night of monitoring at the clinic. Severe cases can need several days in the hospital and leave lasting damage, especially to the kidneys. That's why cooling them right away matters so much.

Can a dog get heatstroke indoors?

Yes. It happens in very hot, poorly ventilated homes, sunrooms, patios and yards in full sun, or in a crate next to a window. It's more likely in flat-faced, older or overweight dogs. Always leave cool water and a shaded area, and during heat waves, use a fan or air conditioning.