Every summer, cases of heatstroke in dogs surge at veterinary clinics — often after a simple walk in the sun or a few minutes too many in a car. Unlike us, dogs sweat very little and regulate their temperature almost entirely through panting. As a result, their body temperature can rise dangerously fast, with consequences that can be irreversible within minutes. Knowing how to spot the warning signs and react without delay can literally save your dog's life. Here's everything you need to know to protect your companion during hot weather.
Why are dogs so vulnerable to heat?
Dogs have very few sweat glands, concentrated in their paw pads. Their main way of releasing heat is panting, a mechanism far less efficient than human sweating, especially when the surrounding air is already hot and humid. On top of that, their coat, while offering some protection from the sun, also traps body heat. Once the outside temperature climbs above 30°C, or even lower in high humidity, panting alone is no longer enough to maintain a normal body temperature, which is usually between 38 and 39°C. Beyond 41°C, cells begin to suffer damage and vital organs can be harmed within minutes.
The heatstroke symptoms you must recognize urgently
Heatstroke progresses very quickly, so it's essential to know how to spot the earliest signs. Loud, excessive panting, bright red gums or tongue, and thick, abundant drooling are often the very first clues. These are followed by weakness, an unsteady gait, vomiting, or diarrhea — sometimes tinged with blood in the most serious cases. If nothing is done, the dog may start trembling, have seizures, and then lose consciousness. A dog that refuses to move, desperately seeks shade, or collapses after exertion in hot weather needs immediate help: every minute counts.
Which dogs are most at risk?
Some dogs are far more exposed than others. Brachycephalic breeds such as the French Bulldog, Pug, or Boxer already struggle to breathe normally, which greatly reduces the effectiveness of panting. Older dogs, overweight dogs, and those with heart or respiratory conditions also tolerate heat very poorly. Puppies, whose temperature-regulation system isn't fully mature yet, along with dogs with thick or dark coats, are also among the sensitive profiles. Finally, a dog left in a car — even with the windows cracked and parked in the shade — remains one of the most dangerous situations: the interior can exceed 50°C within just a few minutes, even in moderate outside temperatures.
Good habits to prevent heatstroke
Prevention remains the best protection. Favor walks early in the morning or in the evening, when the pavement and air are cooler, and avoid any intense physical activity during the hottest hours of the day. Always leave fresh water available, both at home and on walks, and offer shade regularly. Indoors, a fan, a cool room, or an accessible water source can make a real difference. Never leave a dog alone in a car, even for a few minutes. Finally, test the pavement with the back of your hand before a walk: if it's too hot for you, it's too hot for their paw pads too.
Heatstroke: life-saving steps while waiting for the vet
If you suspect heatstroke, the absolute priority is to lower the dog's temperature gradually — never use ice-cold water, which would cause a counterproductive thermal shock. Move the dog immediately to shade or a cool, ventilated spot, then wet them with lukewarm or cool water, particularly on the belly, armpits, and paw pads, while promoting airflow. Offer water to drink without forcing it. These steps are never a substitute for veterinary care: even if the dog seems to recover, heatstroke can cause internal complications (kidney failure, clotting disorders) that only appear several hours later. Contact a vet urgently at the first signs.
After the episode: long-term monitoring and prevention
A dog that has already suffered heatstroke remains more fragile when facing high temperatures afterward: their organs, particularly the kidneys and liver, may have been affected even without visible after-effects. A veterinary follow-up in the days that follow is therefore recommended, sometimes with blood tests. In the longer term, stay extra vigilant during future heatwaves, adapt their activities to the weather, and always keep the warning signs in mind. A dog that has already suffered from heat deserves special attention every summer.
In short
Heatstroke is one of the most common — and most preventable — emergencies of the warm season. By understanding why your dog struggles to regulate its temperature, learning to spot the early signs, and adopting a few simple daily habits, you significantly reduce the risks. And when in doubt, it's always best to seek care quickly: when it comes to heatstroke, how fast you react makes all the difference.
Frequently asked questions
At what temperature is a dog at risk of heatstroke?
The risk increases significantly once the thermometer passes 25 to 30°C, especially with high humidity, physical exertion, or for sensitive breeds. Above 30°C, vigilance should be at its highest, particularly during the middle of the day.
How long does it take for a dog to suffer heatstroke in a car?
Just a few minutes can be enough. Even with the windows cracked and parked in the shade, a car's interior can exceed 50°C in 10 to 15 minutes, making it one of the most dangerous situations.
What are the very first warning signs to watch for?
Excessive, loud panting, bright red gums or tongue, thick and abundant drooling, and restlessness or constantly seeking shade are the first signals not to ignore.
Should you use ice-cold water to cool down a dog?
No. Ice-cold water causes vasoconstriction, which actually slows down heat loss and can trigger a thermal shock. Always use lukewarm or cool water, applied gradually.
Can heatstroke be fatal in dogs?
Yes. Without prompt treatment, heatstroke can lead to organ failure and be fatal within just a few hours. It is a genuine veterinary emergency.
Which dog breeds are most exposed?
Brachycephalic breeds (French Bulldog, Pug, Boxer, Shih Tzu…), older dogs, puppies, and overweight or thick-coated dogs, or those with heart or respiratory conditions, are particularly at risk.
Can you still walk your dog in summer?
Yes, as long as you adjust the timing. Favor walks early in the morning or in the evening, avoid the hottest hours, and always test the pavement temperature with the back of your hand before heading out.
Is excessive panting always a sign of heatstroke?
Not always, but if it comes with weakness, heavy drooling, or very red gums, it should raise immediate concern and prompt you to act without delay.
Should you see a vet even if the dog seems better after being cooled down?
Yes, always. Internal complications such as kidney failure can appear several hours after the episode, even when the dog's overall condition seems to be improving.
How can you set up your home to reduce the risk of heatstroke?
Ensure good airflow, keep shutters closed during the hottest hours, always leave fresh water accessible, and provide a cool, shaded spot where your dog can retreat freely.