When the Trail Gets Hot: Signs of Overheating & Heatstroke in Dogs

By Mary van Kriedt, CCTA/CCDT Certified Positive Reinforcement Dog Trainer & Founder of FreeRun Leashes™ Inc.

One of the things I love most about having a dog is getting outside together.

Some of my favorite time with Quinn is spent hiking, exploring new trails, going to the beach, or simply being outdoors together.

But as much as Quinn loves an adventure, it is my job to pay attention to something he cannot always judge for himself: when his body is getting too hot.

Dogs regulate their body temperature very differently than we do, and overheating is something I take seriously anytime Quinn and I are outside, especially when the weather is warm or humid.

The tricky part is that a dog can go from simply being hot to being in trouble faster than many people realize.

And our dogs are not always very good at telling us when they have had enough.

High-energy dogs in particular may happily keep hiking, running, swimming, or chasing a ball even when their bodies would be better off stopping.

Knowing how dogs cool themselves, the early signs of overheating in dogs, the symptoms of heatstroke, and what to do in an emergency can make a very real difference.

How Do Dogs Regulate Their Body Temperature?

A dog's normal body temperature is approximately 100.5°F to 102.5°F, already several degrees warmer than ours.

Humans have sweat glands over most of our bodies, so sweating is one of our primary ways of cooling ourselves.

Dogs do have functioning sweat glands in their paw pads, but sweating plays only a small role in regulating their temperature.

A dog's main cooling system is panting.

When a dog pants, air moves rapidly across the moist surfaces of the mouth, tongue, and respiratory tract. As that moisture evaporates, it helps remove heat from the body.

Dogs also increase blood flow toward the skin, which helps release additional heat.

It is a remarkably effective system, until environmental conditions or strenuous activity make it difficult for the body to keep up.

High humidity is particularly important because panting relies on evaporation. As humidity increases, evaporation becomes less efficient, making it harder for a dog to cool down.

That is one reason I never decide whether an outing with Quinn is safe by looking at the temperature alone.

The temperature, humidity, sun exposure, shade, intensity of the activity, Quinn's physical condition, and how he is behaving that day all matter.

Signs of Overheating in Dogs: What Should You Look For?

Panting by itself does not necessarily mean your dog is overheating.

If Quinn has just run up a hill and is panting, his body is doing exactly what it is designed to do.

What I pay attention to is how hard he is panting, how quickly he recovers, and whether anything else about his behavior has changed.

This is where knowing your own dog becomes incredibly important.

Early signs of overheating in dogs can include:

• Heavy or excessive panting
• Panting that does not begin to settle after stopping activity
• Seeking shade or water
• Suddenly slowing down or lagging behind
• Reluctance to continue walking, running, or playing
• Restlessness or agitation
• Excessive drooling
• A very red tongue or gums
• Rapid or difficult breathing
• Vomiting or diarrhea

As heat-related illness becomes more serious, you may see:

• Weakness
• Confusion or unusual behavior
• Poor coordination
• Difficulty breathing
• Collapse
• Seizures

Do not wait for those dramatic symptoms before doing something.

If Quinn suddenly starts looking for every patch of shade, slows down, lies down, or begins telling me through his behavior that he has had enough, I listen.

That is not the time to encourage him to push through another mile.

What Is Heatstroke in Dogs?

Heatstroke in dogs is a life-threatening medical emergency.

It occurs when a dog's body temperature becomes dangerously elevated and the body can no longer cool itself effectively.

Cornell University College of Veterinary Medicine notes that a dog's normal temperature is between 100.5°F and 102.5°F and describes heatstroke as occurring when the dog's temperature rises to approximately 105°F or higher and they are unable to regulate it.

The longer a dog's internal temperature remains dangerously high, the greater the potential for damage.

Severe heatstroke can affect organs throughout the body and lead to kidney injury, abnormal blood clotting, shock, neurological problems, and death.

And heatstroke does not happen only when a dog is trapped in a hot car.

Dogs can develop heat-related illness during:

• Hiking
• Running
• Long walks
• Playing fetch
• Dog sports
• Beach outings
• Camping trips
• Strenuous play
• Exercise in warm or humid conditions

In fact, exercise itself can generate a tremendous amount of body heat.

So don't assume that because the weather doesn't feel extremely hot to you, your dog cannot overheat.

Which Dogs Are Most at Risk for Heatstroke?

Any dog can overheat, but some dogs are at greater risk.

These include:

• Flat-faced or brachycephalic dogs such as Bulldogs, Pugs, and French Bulldogs
• Older dogs
• Very young dogs
• Overweight dogs
• Dogs with thick coats
• Dogs with heart or respiratory conditions
• Dogs exercising strenuously in warm or humid conditions

Flat-faced dogs are particularly vulnerable because their shortened airways can make panting less efficient.

But young and athletic does not necessarily mean safe.

Sometimes the enthusiastic, high-drive dog is the one we have to watch most closely.

Quinn loves to go.

If we are having fun, he is not going to pull out a weather app, check the humidity, and suggest we turn around.

That part is up to me.

What Should You Do if Your Dog Starts Overheating?

The best time to intervene is before overheating progresses to heatstroke.

If your dog is panting much harder than normal, slowing down, looking for shade, reluctant to continue, or simply doesn't seem right, stop the activity.

Get your dog into the shade or another cool, well-ventilated area.

Offer water.

Begin cooling them with water if necessary.

Give them time to recover.

And be willing to turn around.

There is nothing to be gained by testing how much farther your dog can go.

How to Cool an Overheated Dog

If you believe your dog is developing serious heat-related illness or heatstroke, current veterinary guidance emphasizes acting quickly.

The Royal Veterinary College uses an easy-to-remember phrase:

Cool first, transport second.

That does not mean delaying veterinary care. It means beginning cooling immediately rather than waiting until you reach the veterinary hospital.

1. Stop the Activity Immediately

Move your dog out of direct sunlight and into shade, air conditioning, or another cool, well-ventilated place.

If Quinn and I were a mile from the car, I would not make him hike that mile before I started cooling him.

I would start where we were.

2. Use Water to Begin Cooling Your Dog

Pouring or spraying water over the dog's body while providing air movement from a breeze, fan, or air conditioning can help cool the body through evaporation.

Current Royal Veterinary College guidance states that the water does not have to be a perfect temperature. The important thing is that it is cooler than the dog and that cooling begins quickly.

For young, healthy, conscious dogs, cold-water immersion can also be an effective rapid-cooling method.

For older dogs, dogs with underlying medical conditions, or dogs who are weak or compromised, pouring or spraying water over the body combined with moving air is a recommended approach.

If the only option available is a hose, remember that water sitting inside a hose in direct sun can become extremely hot.

Let the hose run first until you know the water coming out is safe.

3. Offer Water, but Don't Force Your Dog to Drink

If your dog is conscious and interested in drinking, offer small amounts of water.

Never force water into the mouth of a weak, confused, collapsing, or unconscious dog.

4. Contact Your Veterinarian or an Emergency Veterinary Hospital

Heatstroke requires veterinary care.

Once you have begun cooling your dog, contact your veterinarian or the nearest emergency hospital and tell them what is happening.

Continue cooling during transportation whenever possible.

Use the air conditioning and keep air moving around your dog.

5. Have Your Dog Evaluated Even if They Seem Better

This is extremely important.

A dog may appear much better after cooling while internal complications from heatstroke are still developing.

Heatstroke can cause kidney injury, blood-clotting abnormalities, shock, and damage to other organs that you cannot see simply by looking at your dog.

If I genuinely suspected Quinn had suffered heatstroke, I would have him evaluated by a veterinarian even if he seemed to bounce back after being cooled.

How to Prevent Heatstroke in Dogs on Hikes and Walks

I am a big believer in thinking ahead rather than trying to solve a problem once Quinn and I are already several miles down a trail.

Before heading out on a warm day, I think about:

• Temperature and humidity
• What time of day we will be out
• How much direct sun the trail gets
• How much shade is available
• How strenuous the route will be
• How much water I need to carry for both of us
• Whether there are safe water sources along the way
• How Quinn is feeling that particular day
• How far we still have to travel once we turn around

Whenever possible, I choose early morning or later evening outings during hot weather and avoid strenuous exercise during the hottest part of the day.

I also bring a collapsible water bowl and enough water that Quinn can drink throughout the outing.

And I remind myself of something that is surprisingly easy to forget:

The return trip counts.

It is easy to reach a beautiful spot and think, "Let's just go a little farther."

But every extra half mile out is another half mile Quinn has to travel back.

Sometimes turning around earlier than planned is the smartest decision you can make.

Don't Wait for Your Dog to Collapse

For me, this may be the most important takeaway from this entire article.

There is a big difference between recognizing the early signs of overheating in your dog and waiting until you are dealing with advanced heatstroke.

If Quinn is panting harder than normal, taking longer to recover, slowing down, seeking shade, refusing to continue, or simply does not seem like himself, that is enough for me to stop and reassess.

Find shade.

Offer water.

Cool your dog down.

Let them recover.

And if necessary, call it a day.

There is no hike, run, beach day, or game of fetch worth pushing a dog into trouble.

Frequently Asked Questions About Dogs and Overheating

Do dogs sweat?

Yes, but not the way humans do. Dogs have functioning sweat glands primarily in their paw pads, but sweating provides only a small amount of cooling.

Dogs rely mainly on panting and other mechanisms for regulating their body temperature.

Why do dogs pant when they are hot?

Panting allows moisture to evaporate from the dog's mouth, tongue, and respiratory tract.

This evaporation helps release body heat and lower body temperature.

How can I tell normal panting from overheating?

Pay attention to what is normal for your dog.

Panting after exercise is expected.

Panting that becomes frantic or excessive, does not begin to settle with rest, or occurs along with excessive drooling, weakness, seeking shade, reluctance to move, vomiting, confusion, or poor coordination should be taken seriously.

Can a dog get heatstroke when it isn't extremely hot outside?

Yes.

Heatstroke can result from strenuous exercise as well as environmental heat.

Humidity, sun exposure, breed, age, physical condition, and intensity of exercise all affect a dog's ability to stay cool.

Should I take my dog to the vet after heatstroke if they seem better?

Yes.

Suspected heatstroke is a veterinary emergency.

Internal organ damage and other complications may not be immediately visible, even if your dog appears to recover after cooling.

Know Your Dog

One of the things I love about spending so much time outdoors with Quinn is that I have gotten to know his rhythms.

I know his normal pant.

I know how quickly he usually recovers after running.

I know how he moves when he is feeling good.

And I know when something just looks a little different.

You know those things about your dog too.

Pay attention to the small changes.

Our dogs trust us to make decisions they cannot always make for themselves.

Quinn would follow me to the moon if I asked him.

But he doesn't know whether we have another three miles left to get back to the car, whether the temperature is going to climb another ten degrees, or whether the trail ahead has any shade.

I do.

And sometimes being a good adventure partner means being the one who says, "That's enough for today."

There will always be another trail.

Veterinary Sources

The health and first-aid information in this article is based on guidance from the Cornell University College of Veterinary Medicine, the Royal Veterinary College, and the American Animal Hospital Association (AAHA).

This article is intended for general education and should not replace advice from your veterinarian. Suspected heatstroke is a veterinary emergency.

For factual support, Cornell confirms the normal canine temperature range, the roughly 105°F heatstroke threshold, the major warning signs, organ risks, and need for immediate cooling and veterinary care.

The Royal Veterinary College supports the “cool first, transport second” language and rapid water-based cooling guidance used here.