Heatstroke in Dogs: Prevention and Warning Signs

On a warm day, it is normal to see your dog panting after a walk or a game of fetch. Panting is a dog’s primary way of cooling down. But sometimes, this normal behavior can shift into something more serious. If the panting becomes frantic, noisy, or is paired with distress and weakness, it could be an early sign of overheating, a condition that can quickly become a life-threatening emergency known as heatstroke.

Understanding the difference between a dog who is simply warm and one who is in real danger is essential for any dog owner. Heatstroke can happen much faster than many people realize, and not just on scorching summer days. Knowing the risks, recognizing the warning signs, and knowing what to do can save your dog’s life.

What is heatstroke?

Heatstroke is the most severe form of overheating (hyperthermia). It happens when a dog’s body absorbs more heat than it can get rid of. Their internal temperature rises to a dangerously high level, causing widespread inflammation and damage to organs like the brain, liver, kidneys, and intestines. If not treated immediately, it can be fatal.

Dogs are not built to handle heat as well as people are. Humans are covered in sweat glands that help cool the body through evaporation. Dogs, on the other hand, have very few sweat glands, with most located in their paw pads. Their main cooling mechanism is panting. As a dog breathes rapidly, air moves over the moist surfaces of their tongue and respiratory tract, which helps heat escape. This process is much less efficient than sweating, especially in high humidity when the air is already full of moisture, making evaporation difficult.

Which dogs are most at risk?

While any dog can suffer from heatstroke, some are more vulnerable than others. It is important to be extra cautious if your dog falls into one of these categories.

Brachycephalic (flat-faced) breeds

Dogs with short snouts, such as Pugs, French Bulldogs, English Bulldogs, Boxers, and Shih Tzus, are at a very high risk. Their compressed airway anatomy makes it physically difficult for them to pant effectively. They simply cannot move enough air to cool themselves down efficiently, making them overheat very quickly.

Other risk factors

Giant breeds and overweight dogs: Larger, heavier dogs have more body mass and insulation (fat), which makes it harder for them to dissipate heat. You can learn how to check if your pet is overweight at home.
Thick or dark-colored coats: A dense coat can trap heat, while a dark coat absorbs more heat from the sun.
Puppies and senior dogs: The very young and the very old have a harder time regulating their body temperature. There are many ways of keeping your senior dog comfortable as they age.
Dogs with medical conditions: Heart disease, respiratory problems (like laryngeal paralysis), and neurological conditions can impair a dog’s ability to cool down.
Extremely active dogs: Working or sporting dogs who do not get enough breaks and water are at risk of exertional heatstroke, even on milder days.

Common causes of heatstroke

Most cases of heatstroke are preventable. Understanding the common situations that lead to it is the first step in keeping your dog safe.

Leaving a dog in a vehicle

This is the most well-known cause, yet it continues to happen. The temperature inside a parked car can rise to dangerous levels within minutes, even on a seemingly mild, sunny day. Cracking the windows does very little to slow this process. A car acts like an oven, and leaving a pet inside, even for a moment, can have tragic consequences.

Excessive exercise in the heat

Taking a dog for a run or engaging in intense play during the hottest part of the day is a major risk. Dogs are often so eager to please or enjoy the activity that they will push themselves past their physical limits without showing signs of distress until it is too late. Pavement and asphalt can also become extremely hot, burning a dog’s paw pads.

Lack of shade and water

A dog left in a yard or on a patio without access to adequate shade and plenty of fresh, cool water can easily overheat. A doghouse can become very hot inside and may not provide sufficient relief. The sun moves, so an area that was shady in the morning might be in direct sun by the afternoon.

High humidity

Humidity is a major factor. When the air is heavy with moisture, a dog’s panting is much less effective at cooling them down. This is why a humid, warm day can be more dangerous than a hotter, dry day.

How to prevent heatstroke

Prevention is straightforward and relies on common sense and planning during warm weather.

Never leave your dog in a car: Not even for a minute. The temperature inside a car can rise to dangerous levels very quickly, even on mild days.
Time your walks carefully: Walk your dog during the coolest parts of the day, such as early morning and late evening. Avoid walks during the peak heat of midday and afternoon.
Check the pavement: Before you walk, place the back of your hand on the pavement. If it is too hot for you to hold it there for five seconds, it is too hot for your dog’s paws.
Provide constant access to shade and water: Whether indoors or outdoors, ensure your dog always has a shady place to rest and multiple sources of fresh, cool water. On walks, carry water for your dog.
Avoid strenuous activity: On hot and humid days, limit exercise. Opt for gentle indoor play or training sessions in an air-conditioned space instead of a long run or vigorous game of fetch outside.
Consider cooling aids: Cooling mats, wading pools, or sprinklers can help your dog stay comfortable in a supervised environment. Wetting a dog’s coat with cool water before they go outside can also help, but this is less effective for dogs with very thick double coats.
Pay attention to your dog: Watch your dog for signs of fatigue or overheating during any activity. If they seem tired or are panting heavily, stop immediately, find a cool spot, and offer water.

Warning signs of heatstroke

Recognizing the early signs of overheating is critical. If you see these, you must act immediately to cool your dog down and seek veterinary advice.

Early to moderate signs

Frantic, heavy, or noisy panting
Excessive drooling with thick, ropey saliva
Bright red gums and tongue
Restlessness or agitation
Vomiting or diarrhea
Appearing weak, dizzy, or uncoordinated

Advanced, life-threatening signs

Gums that turn pale, blue, or gray
Confusion or disorientation
Stumbling, staggering, or inability to stand
Collapse or loss of consciousness
Seizures

If a dog’s internal temperature continues to rise, it can lead to organ failure, brain damage, and death. The progression from early signs to advanced signs can be very rapid.

What to do if you suspect heatstroke

If you see signs of heatstroke, it is a medical emergency. Your goal is to start cooling your dog immediately while preparing for transport to a veterinary clinic.

Move your dog to a cooler area right away. Get them out of the sun and into an air-conditioned room or a shady spot.
Begin cooling with water. Use cool, not ice-cold, water. Douse your dog’s body with a hose, shower, or wet towels. Focus on the groin, armpits, neck, and paws, where major blood vessels are close to the skin. Do not use ice or ice-cold water, as this can cause blood vessels to constrict, which traps heat and can lead to shock.
Use a fan. Direct a fan towards your dog as you wet them. The moving air will help speed up evaporative cooling.
Do not let your dog drink excessive water. Offer small amounts of cool water if they are conscious and able to drink. Do not force water into their mouth, as they could inhale it.
Call a veterinarian immediately. Inform them that you are on your way with a dog suffering from heatstroke. They can give you further instructions and prepare for your arrival. Your dog needs to be seen by a vet even if they seem to be recovering, as internal damage may not be immediately obvious.

Do not attempt to bring your dog’s temperature down too far or too fast at home. The cooling process should be controlled and monitored by a veterinary professional to avoid other complications. The goal of at-home first aid is to start the cooling process before and during transport to the vet.

When to call your vet

Heatstroke is always an emergency. If you suspect your dog is overheating, start first aid and contact a veterinarian right away. Call ahead to let the vet or an emergency clinic know you are coming.

Emergency signs: go now

Vomiting or diarrhea
Weakness, stumbling, or dizziness
Confusion or disorientation
Pale or blue-tinged gums
Collapse or loss of consciousness
Seizures
Difficulty breathing

Book an appointment soon

For a follow-up check after any episode of overheating, even if it seemed mild.
To discuss your dog’s specific risk factors for heatstroke.
To get advice on safe exercise routines for your dog’s breed and age.
For a general wellness check if you have concerns about your dog’s breathing or stamina.