Heatstroke in Dogs: Signs, Symptoms and What to Do

Paige Montes

39 Posts

Summer is a wonderful time to be a dog owner. Long walks at the park, trips to the lake, and lazy afternoons in the backyard are what life is all about. But as the temperature climbs, a hidden danger creeps in. You might not see it coming until it is almost too late, I’m talking about heatstroke.

Unlike humans, dogs cannot cool down efficiently. They do not sweat through their skin. Instead, they rely on panting to release heat. When the air around them is hotter than their body, that system stops working. Heatstroke happens quickly, and it can be deadly in minutes.

The good news is that you can save your dog’s life. But you have to know what to look for, and you have to act fast. In this guide, we will walk through the warning signs of heat exhaustion, the exact first aid steps you must take, and the common mistakes that could make things worse.

What is Heatstroke? Understanding the Silent Emergency

Before we talk about symptoms, let us understand what is actually happening inside your dog’s body. Heatstroke is not just being “too hot.” It is a life-threatening medical emergency.

Why Dogs Overheat Faster Than Humans

Here is something many dog owners do not realize. Humans have sweat glands all over our bodies. When we get hot, we sweat. That sweat evaporates off our skin, and that evaporation pulls heat away from our bodies. It is an incredibly efficient cooling system.

Dogs, on the other hand, have very few sweat glands. The only place they really sweat is through their paw pads. That is not nearly enough to cool a whole body.

So how do dogs cool down? They pant.

When a dog pants, moisture evaporates from their tongue and their lungs. That evaporation should, in theory, cool them off. But here is the problem. Panting only works if the air they are breathing in is cooler than their body temperature. On a hot, humid day, panting is like trying to cool your kitchen by opening the oven door. You are just moving hot air around.

The Critical Threshold: When Heat Becomes Deadly

A healthy dog’s normal body temperature is around 101.5°F (38.6°C). Once their temperature hits 104°F (40°C) , they have entered the danger zone. This is called heat exhaustion.

At 106°F (41°C) or higher, heatstroke sets in. At this temperature, the proteins inside the body’s cells start to break down. Organs begin to fail. The brain can swell, and blood clotting stops working correctly. Without immediate treatment, death can follow.

The scary part is how fast this happens. In extreme conditions, a dog can go from healthy to critical organ failure in less than 15 minutes.

Early Warning Signs of Heatstroke in Dogs

Not all heatstroke cases look the same. Some dogs show mild signs first. Others seem fine one moment and collapse the next. That is why you need to know the progression of symptoms.

Stage 1: Mild Heat Exhaustion Symptoms

These are the early warning signs. If you see these, you still have time to prevent an emergency. Stop all activity immediately and start cooling your dog down.

• Heavy, non-stop panting. Not the happy, slightly open mouth panting you see after fetch. This is desperate, loud, and fast.
• Bright red gums and tongue. When a dog gets too hot, blood vessels rush to the surface to try to release heat. That makes their mouth look deep red or purple.
• Thick, sticky drool. Normal drool is thin. Overheated drool becomes thick and stringy.
• Restlessness or pacing. Your dog cannot sit still because they are uncomfortable. They may dig at the ground or try to find a cool spot.
• Seeking cool surfaces. If your dog suddenly lies down on the bathroom tile or presses their belly against the grass, listen to them.

Stage 2: Advanced Heatstroke Symptoms (Critical Emergency)

If you see any of these signs, your dog is in danger of dying. Do not wait. Do not “see if they get better.” Start first aid immediately and head to the vet.

• Sudden stopping of panting. This is very dangerous because it looks like the dog has calmed down. In reality, they have stopped panting because their body has given up. They can no longer regulate their temperature at all.
• Vomiting or diarrhea. You may even see blood in these fluids. This means the intestinal lining is breaking down.
• Disorientation or stumbling. Your dog walks into walls, seems confused, or cannot walk in a straight line.
• Pale, grey, or blue gums. This is a sign of shock. The body is shutting down blood flow to non-essential areas.
• Seizures or collapse. This is the final stage. The brain is swelling, and organ failure is happening.

If you see stage 2 symptoms, do not waste a single second.

At-Risk Breeds: Which Dogs Overheat the Easiest?

Every dog can get heatstroke. But some dogs are much more likely to overheat than others. If you own one of these breeds, you need to be extra careful.

Brachycephalic (Flat-Faced) Breeds

The highest risk group is flat-faced dogs. Veterinarians call them brachycephalic breeds. These dogs have the same amount of soft tissue inside their heads, but their skulls are squished shorter. That means their airways are narrowed. They simply cannot move enough air to cool themselves effectively.

The most at-risk breeds include:

• British Bulldog
• French Bulldog
• Pug
• Boxer
• Shih Tzu
• Boston Terrier

These breeds are several times more likely to suffer heatstroke than other dogs. On a warm day, a Bulldog can overheat in the time it takes you to run a five-minute errand.

Other High-Risk Categories

Even if your dog has a nice long snout, other factors can put them at risk.

• Thick-coated breeds. Huskies, Malamutes, Chow Chows, and German Shepherds have dense double coats designed for cold weather. In summer heat, that coat works against them.
• Giant breeds. Great Danes, Saint Bernards, and Newfoundlands generate a lot of body heat just by existing. Their large size makes it harder to cool down.
• Puppies and senior dogs. Very young dogs cannot regulate their temperature well yet. Very old dogs have weaker hearts and lungs. Both are vulnerable.
• Overweight dogs. Fat tissue acts as insulation. An overweight dog traps heat inside their body.
• Dogs with medical conditions. Heart disease, laryngeal paralysis, and breathing disorders all make heatstroke more likely.

Just because your dog is not on this list does not mean they are safe. Watch every dog closely in the heat.

Immediate First Aid: What to Do Before It’s Too Late

You have spotted the signs. Now what? Panic wastes precious seconds. Heatstroke can turn deadly in minutes, but the first three minutes are your best chance to save your dog’s life. Stay calm and follow these steps in order. 

The First 3 Minutes: Critical Cooling Steps

Step 1: Move the dog immediately. Get them out of the sun, out of the car, and away from hot pavement. Find air conditioning if possible. If you are outside, find shade. Even a little bit of relief helps.

Step 2: Use cool water, not ice water. This is the most important rule. Fill a hose, a bucket, or a sink with cool tap water. Pour it over your dog’s entire body. Focus on the belly, the armpits, and the paw pads. These areas have blood vessels close to the skin, so cooling them cools the blood inside.

Why not ice water? Ice water causes the blood vessels on the skin to clamp shut. That traps the heat inside the body. Your dog’s skin will feel cold, but their organs will still be cooking. Ice water can actually raise the internal temperature. Stick with cool water.

Step 3: Create airflow. Turn on fans. Crank the car’s air conditioning. Even a hand fan helps. Evaporation is what cools the body. Moving air speeds up evaporation dramatically.

Step 4: Offer small drinks. If your dog is alert and standing, offer them small sips of cool water. Do not let them gulp. Gulping can lead to vomiting or bloat. If your dog is wobbly, unconscious, or not interested, do not force water into their mouth. They could inhale it into their lungs.

Step 5: Stop cooling at 103°F. If you have a rectal thermometer, check the temperature every five minutes. Once your dog’s temperature falls to 103°F (39.4°C), stop cooling. If you keep going, you can drop them into hypothermia.

The “Don’t List” – Common Mistakes That Kill

Even well-meaning dog owners make mistakes. Avoid these at all costs.

• Do not use ice or ice water. We covered this, but it is worth repeating. Ice water is dangerous.
• Do not cover your dog with wet towels. This is a very common mistake. People think a cool wet towel will help. In reality, a wet towel acts like a blanket. It traps heat against the dog’s body. As the towel warms up, it insulates the dog. If you use towels at all, put them under the dog, not over them. Or wet the towel and then remove it right away.
• Do not force water into the mouth. An unconscious dog cannot swallow. Pouring water into their mouth sends it straight to the lungs. That causes aspiration pneumonia, which is another life-threatening condition.
• Do not wait to see if they improve. Heatstroke does not get better on its own. Every minute you wait, the damage gets worse.

What Happens at the Vet?

You did a great job cooling your dog. They are panting less. They seem more alert. Does that mean you are done? The answer is: No.

Beyond First Aid: Internal Damage You Cannot See

Here is the hard truth. Even if your dog looks fine after cooling, their internal organs may still be failing. Heatstroke damages the lining of the intestines. That allows bacteria to leak into the bloodstream, causing a deadly infection. It also damages the kidneys, the liver, and the heart muscle.

Veterinarians call this “systemic inflammatory response syndrome.” It often shows up 12 to 24 hours after the heatstroke happened.

When you take your dog to the emergency vet, they will:

• Run blood tests to check organ function.
• Start IV fluids to support blood pressure and kidney health.
• Give medications to protect the stomach and intestines.
• Provide oxygen therapy if the dog is struggling to breathe.
• Monitor for seizures or blood clotting problems.

Do not skip this step. A dog that seems fine at 6 PM can crash at midnight. Always take a heatstroke dog to the vet, even if they appear to have recovered.

Prevention: Keeping Your Dog Safe in Summer Heat

You have learned the warning signs of heatstroke. You know the first aid steps by heart. But here is the truth: The best treatment is prevention.

Even a perfect emergency response can still lead to organ damage. And a trip to the emergency vet is stressful, expensive, and scary for everyone. Prevention is free, and simple. So here’s how to protect your best friend all season long.

The Car Rule: Just Don’t Do It

Never, ever leave your dog in a parked car. Not for five minutes. Not with the windows cracked. Not in the shade.

On a 75°F day, the inside of a car can reach 100°F in ten minutes. On a 90°F day, the inside of a car can hit 120°F in the same amount of time. Cracking the windows does almost nothing.

In many states, leaving a dog in a hot car is a criminal offense. Police officers and animal control officers can break your window to rescue the dog. You could face fines, jail time, and losing your pet. Just leave your dog at home on warm days.

Walk Timing and Surface Safety

Walk your dog early in the morning or late in the evening. The sun is lower, and the pavement is cooler.

Speaking of pavement. Before every walk, test the ground with your bare hand. Press your palm down for five seconds. If it is too hot for your hand, it is too hot for your dog’s paws. Burnt paw pads are painful and take weeks to heal.

Smart Accessories for Summer

You do not have to stay inside all summer. Just prepare properly.

• Cooling vests. These vests use evaporative technology to keep your dog’s core temperature down. Wet the vest, wring it out, and put it on your dog. It stays cool for hours.
• Cooling mats. Dogs cool themselves through their bellies. A cooling mat gives them a cool surface to lie on.
• Kiddie pools. A shallow plastic pool filled with a few inches of cool water is a summer lifesaver. Many dogs will lie right down in it.
• Frozen treats. Blend up dog-safe fruits (blueberries, watermelon, banana) with water or plain yogurt. Freeze them in ice cube trays or Kong toys. Your dog gets a cool snack and hydration at the same time.
• Multiple water bowls. Put water bowls in every room. Add ice cubes to keep the water cool longer. Bring a collapsible bowl and a bottle of water on every walk.

Heatstroke moves fast. One minute your dog is playing. The next minute, they are fighting for their life. But you already have the tools to stop that from happening.

Wrapping Up

Heatstroke is fast, silent, and deadly. One minute your dog is playing, the next , they are fighting for their life. But you already have the tools to stop that from happening.

Here is what to remember:

• Spot the signs early. Heavy panting, red gums, and thick drool are your first warnings.
• Act immediately. Move your dog to shade or A/C. Pour cool (not cold) water over their belly, armpits, and paws. Create airflow with fans or a car AC.
• Avoid the big mistakes. No ice water. No wet towels left on the dog. No waiting to see if they improve.
• Go to the vet anyway. Internal damage can show up hours later, even if your dog looks fine.

You know your dog better than anyone. Trust your gut. When in doubt, cool them down and get to the vet. Those few minutes of action are the difference between a close call and a tragedy.

Stay alert, stay safe, and enjoy the summer with your best furry friend!

Disclaimer: This post is for informational purposes only and is not a substitute for veterinary care. If you suspect your dog is experiencing heatstroke, contact your veterinarian.