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This guide is a home-care support tool. With heatstroke, every minute counts: start cooling your pet and reach us right away at 514 223-1197.
Recognizing heatstroke
Heatstroke happens when the body can no longer shed heat. Dogs and cats cool themselves mainly by panting, and a little through their paw pads: in hot weather, during exercise, or in a poorly ventilated space, those systems are quickly overwhelmed. Here are the signs, from subtle to severe.
In dogs
Early signs
- Heavier, faster panting
- Thick drool, tongue hanging far out
- Seeks shade, slows down, lies down
- Bright-red gums
Severe signs
- Wobbling, weakness, then collapse
- Vomiting or diarrhea (sometimes bloody)
- Confusion, staring, tremors
- Seizures, loss of consciousness
In cats
Early signs
- Fast breathing, seeks cool tile
- Hides, restless, grooms a lot
- Drooling, low energy
- Brick-red gums
Severe signs
- Open-mouth panting
- Bright-red gums or, worse, pale or grey
- Vomiting, unsteady gait
- Collapse, seizures
A panting cat is an emergency
Unlike a dog, a cat almost never pants normally. The one exception: a brief bout of panting after hard play, a stressful car ride, or a spike of heat, which settles within a few minutes as the cat rests and goes back to closed-mouth breathing. Panting at rest, panting that lingers, or panting with any other sign means call us right away: it can point to heatstroke, but also to a breathing or heart problem.
This is an emergency, act now
Weakness or collapse, vomiting or diarrhea, confusion, tremors or seizures, gums that are bright red, pale, or grey, very labored breathing: start cooling immediately (next section) and call us. A rectal temperature above 40 °C confirms heatstroke, but do not wait to measure it before acting.
Cooling: the up-to-date method
The rule has changed. We now know that cold water cools faster and safely: the idea that cold water 'traps the heat' is a myth. The goal: bring the temperature down quickly, then drive to the vet while you keep cooling.
First, get out of the heat
Move your pet into the shade right away, somewhere cool, ventilated, or air-conditioned. Then cool it with COLD tap water: not lukewarm, but not iced either.
Which method for your pet
A young, healthy, fully alert dog
Immerse the body in cold water (a tub, a large bin, a clean body of water), keeping the head above the surface. This is the fastest way to bring the temperature down.
An older, unwell, flat-faced, or overweight dog, a collapsed or unconscious dog, and all cats
Do not immerse (choking risk). Pour or spray cold water over the whole body, continuously, and get air moving (a fan, a draft, air conditioning).
When in doubt, the safe method for every dog and cat: pour cold water over the whole body, continuously, with moving air.
Get out of the heat
Shade, a cool room, ventilated or air-conditioned. Stop all exercise and any walk.
Wet the whole body with cold water
Focus on the belly, groin, armpits, and neck. Keep re-wetting: a layer of water that warms up stops cooling.
Get the air moving
A fan, a draft, or air conditioning over a wet coat speeds cooling up a great deal.
Call us and hit the road
Phone while you cool, then drive with your pet kept wet, windows open or AC on full. Keep cooling on the way.
Stop at the right point
If you have a thermometer, stop cooling once you reach about 39.4 °C (103 °F): the body keeps dropping on its own, and over-cooling causes dangerous hypothermia. No thermometer? Cool for a few minutes, drive, and let the clinic take over.
A little water to drink, without forcing
If your pet is fully alert and wants it, let it sip small amounts of cool (not iced) water. Never pour water into the mouth of a drowsy, collapsed, or unconscious pet: choking risk. Cooling comes before drinking.
Never do this
A few well-meaning reflexes make things worse or cost precious time.
- Give a human fever or pain medicine (acetaminophen or Tylenol, aspirin, ibuprofen or Advil). Heatstroke is not a fever: these do not lower the temperature and are toxic to organs already under strain. Acetaminophen is deadly to cats, even half a tablet.
- Use ice or an ice bath. Cold tap water is enough and avoids over-cooling.
- Rub alcohol on the paw pads: it cools poorly, stresses the animal, and is toxic if licked.
- Leave a wet towel draped on the animal: once it warms up, it insulates and blocks airflow. If a towel is all you have, keep it cold and re-soak it constantly, and do not cover the whole body.
- Force a weak or drowsy animal to drink.
- Leave the animal unattended while cooling.
Even if it recovers, see us
This is the most dangerous trap of heatstroke: the animal can seem to recover, then go downhill in the hours that follow.
A whole-body effect
Heat can injure the kidneys, liver, gut, and blood-clotting system: it does not just 'warm the pet up' for a moment.
A 24-to-72-hour window
This damage can appear or worsen over the next 24 to 72 hours, sometimes over a few days. A pet that looks recovered is not necessarily out of the woods.
Tests that change
Bloodwork that looks normal at first can shift afterward: that is why your veterinarian may want to monitor your pet or repeat tests.
'It seems fine now. Do I still need to come in?'
Yes. After any bout of heatstroke, even a short one and even if your pet seems fully recovered, have it examined the same day. Seeing it early is exactly what helps head off the serious complications.
Seek emergency care, without waiting
Collapse, seizures, vomiting or diarrhea (especially with blood), very difficult breathing, gums that are pale, grey, or bluish, confusion or loss of consciousness: this is a life-threatening emergency.
Who is most at risk
In dogs, the leading cause of heatstroke is not the car: it is exercise in the heat. And some animals overheat far faster than others.
- Flat-faced (brachycephalic) pets: English and French Bulldogs, Pugs, Boxers, Shih Tzus, and among cats the Persian. Their short airways make panting inefficient.
- Thick or double coats and large breeds: Chow Chow, Husky, Golden Retriever, Newfoundland, Maine Coon. Do not shave them: the coat also shields against heat, so just keep it well brushed and mat-free.
- Excess weight and obesity: a healthy weight is one of the most effective prevention levers there is.
- Both extremes of age: very active youngsters, who overdo it, and older or frail pets, who cope poorly with ambient heat.
- A fragile heart or airway: heart disease, a breathing problem, laryngeal paralysis, or a past heatstroke. The risk stays high all through the warm season, and a previous episode offers no protection.
As dangerous as a hot car
A long walk or a play session in full heat is as dangerous as an overheated car. The car is simply a rarer cause, not a less serious one. Above all, it is exercise that needs to be matched to the weather.
Preventing heatstroke
The large majority of heatstroke cases are preventable. A few habits change everything.
- Never leave a pet alone in a car. The interior can climb some twenty degrees in an hour, most of it within the first half hour, and turn deadly even on a mild day around 21 °C. Cracking the windows makes no difference.
- Shift exercise to the cool hours (early morning, late evening) and shorten it when it is hot or humid. Never push a pet that is slowing down or seeking shade.
- Test the pavement: press the back of your hand to the ground for 5 to 7 seconds. Too hot for you? Too hot for its paws.
- Watch the humidity: humid air hampers panting, so a muggy day is more dangerous than the thermometer suggests. Take extra care on smoggy or high-humidex days.
- Always offer fresh water freely, plus shade and airflow. Bring water on walks.
- Never a closed muzzle that blocks panting in the heat (only a basket muzzle, supervised).
Cats too, all year round
In cats, heatstroke is mostly an indoor problem: check the dryer, closets, shed, sunroom, garage, and carrier before closing them. Offer several water spots and cool corners, in every season, not just summer.
A pet trapped in a car?
If an animal is in distress in a vehicle, call 911 first, then the Montreal SPCA line (1-855-711-7575, 24 hours a day, province-wide). Elsewhere in Quebec, reach MAPAQ (1-844-264-6289). Leaving an animal to suffer in a vehicle is an offence. Do not break the window yourself: in Quebec, no law protects a citizen who does.
Your questions, our answers
What owners ask us most often about heatstroke.
It seems fine now. Do I still need to come in?
Cold water or lukewarm?
My cat is panting, is that serious?
How long should I watch it afterward?
Are a fan or a cooling mat enough?
Related guides
Recognize, cool, get seen
At the first sign (abnormal panting, weakness, very red gums), get your pet out of the heat and cool it with cold water, over the whole body, with moving air. Cool first, then drive to the vet while you keep going. Even if it recovers, it needs an exam, because internal damage can surface later. And the best protection is still prevention: shade, water, air, and never a pet alone in a car.
Unsure, or a pet that got very hot?
After heatstroke, even a brief one, a same-day exam can prevent complications. Our team is here to assess your pet.