Signs of Heatstroke in Dogs (And What to Do)

TL;DR: Heatstroke happens when a dog's body temperature climbs past about 104 degrees Fahrenheit and their cooling system can't keep up. Early signs are heavy panting, thick drool, bright red gums, and restlessness. Emergency signs are stumbling, vomiting, diarrhea (sometimes bloody), collapse, seizures, and unresponsiveness. If you suspect heatstroke, move the dog to shade or AC, wet them with cool (not ice-cold) water, offer small sips, and get to a vet immediately, even if they seem to recover. Flat-faced breeds, seniors, puppies, and overweight dogs are highest risk. Prevention is shade, water, smart timing, and never leaving a dog in a car.

Heatstroke is one of the few summer emergencies that can go from "my dog seems a little tired" to life-threatening in under an hour. It is also one of the most preventable. The hard part is that dogs do not tell you they are in trouble until they are already in real danger, and the early signs are easy to wave off as "it's just hot out."

This guide covers exactly what heatstroke looks like at each stage, which dogs are most at risk, the step-by-step response that can save your dog's life, and how to keep it from happening in the first place.

What Heatstroke Actually Is

A healthy dog's body temperature sits around 101 to 102.5 degrees Fahrenheit. Dogs shed heat mainly by panting (evaporating moisture from the tongue and airways) and a little through their paw pads. When the heat coming in (hot weather, exercise, a closed car) outpaces what they can pant off, their core temperature rises.

Heat stress starts around 104 degrees. Once a dog passes roughly 106 degrees, organs begin to fail, the blood's ability to clot breaks down, and the situation becomes life-threatening fast. The longer a dog stays overheated, the more damage stacks up, which is why speed matters so much.

Early Warning Signs (Act Now)

These are the signs that mean "stop, cool down, get water." Catching heatstroke here is the whole game:

• Heavy, rapid panting that does not ease up even when the dog rests
• Thick, sticky, or excessive drool
• Bright red gums and tongue (an early flush as the body tries to dump heat)
• Restlessness or pacing, an inability to settle or get comfortable
• Seeking out cool surfaces, pressing belly to tile or concrete
• Warm to the touch, ears and belly feel hotter than usual

If you see these on a hot day, treat it as the beginning of heatstroke. Move to shade or air conditioning, offer cool water, and start active cooling. Do not wait to see if it gets worse.

Emergency Signs (Go to the Vet Immediately)

These signs mean the dog is in serious trouble and needs veterinary care right away, while you cool them on the way:

• Stumbling, wobbling, or weakness in the legs
• Vomiting or diarrhea, sometimes with blood
• Gums that turn pale, blue, or gray (a sign of shock or oxygen problems)
• Glazed eyes, confusion, or not responding to their name
• Collapse or inability to stand
• Tremors or seizures
• Unconsciousness

At this stage, every minute counts. Begin cooling immediately and get to the nearest open veterinary clinic. Call ahead if you can so they are ready when you arrive.

What to Do, Step by Step

If you suspect heatstroke, follow this sequence:

1. Move the dog out of the heat. Get them into shade, an air-conditioned room, or in front of a fan right away.
2. Start cooling with cool water, not ice water. Pour or hose cool water over the body, focusing on the belly, groin, armpits, and paws where blood runs close to the surface. Ice-cold water and ice baths can actually backfire by constricting blood vessels and trapping heat in the core, so aim for cool, not freezing.
3. Add airflow. Point a fan at the wet dog. Moving air over wet fur speeds evaporation, which is what pulls heat out.
4. Offer small amounts of cool water to drink. Let them sip. Do not force water into a dog that is disoriented or unable to swallow safely.
5. Check temperature if you can. If you have a rectal thermometer, stop active cooling once you reach about 103 degrees so you do not overshoot into hypothermia.
6. Get to a vet, even if they seem better. This is the part people skip and regret. Heatstroke can cause internal damage (kidneys, clotting, brain) that shows up hours later. A dog that "bounced back" can crash that evening. A vet needs to check.

Do not give human medications, do not wait for symptoms to worsen, and do not assume a quick recovery means everything is fine.

Which Dogs Are Most at Risk

Heatstroke can hit any dog, but some are far more vulnerable:

• Flat-faced (brachycephalic) breeds, Bulldogs, French Bulldogs, Pugs, Boxers, Shih Tzus, Boston Terriers. Their compressed airways make panting much less effective, so they overheat in conditions other dogs shrug off. These breeds are overrepresented in heatstroke cases by a wide margin.
• Senior dogs, weaker temperature regulation and often underlying heart or lung issues.
• Puppies, immature systems and a tendency to play past the point of sense.
• Overweight dogs, extra insulation and more cardiovascular strain.
• Double-coated and dark-coated breeds, more insulation and more heat absorption from the sun.
• Dogs with heart disease, respiratory conditions, or laryngeal paralysis.
• Very active dogs who will run themselves into the ground chasing a ball regardless of the heat.

If your dog is in any of these groups, your threshold for caution should be much lower.

The Most Common Causes

Most heatstroke cases trace back to a handful of preventable situations:

• Being left in a parked car. The classic and deadliest cause. A car interior can climb 20 degrees in 10 minutes, even with windows cracked. There is no safe version of this.
• Exercise in the heat. A midday run, a long fetch session, or a hike on a hot afternoon.
• No access to shade or water while left outside.
• Being left in a hot room, sunroom, or garage with poor ventilation.
• High humidity, which quietly cripples a dog's ability to cool by panting even at moderate temperatures.

How to Prevent Heatstroke

Prevention is straightforward and worth building into your summer routine:

• Never leave your dog in a parked car. Not for a minute. Leave them home instead.
• Provide constant shade and fresh, cool water any time your dog is outdoors.
• Exercise early or late. Skip midday activity. Do the pavement hand test before walks.
• Watch the humidity, not just the thermometer.
• Give frozen treats and cold water to help cool from the inside and keep dogs calm in the shade rather than overheating in the yard.
• Keep at-risk dogs (flat-faced, senior, overweight) indoors during the hottest hours.

Frozen treats deserve a mention here because they pull double duty: they nudge a dog's core temperature down and they keep an energetic dog happily occupied somewhere cool instead of charging around in the sun. We built our Pupsicle Starter Kit for exactly this, a just-add-water frozen treat made from real meat, about 20 calories each, no sugar or dairy to upset a stomach on a hot day. A frozen lick mat works the same way for indoor downtime, giving a restless dog a long, calming licking job during the heat of the afternoon. For more on why cold treats are such a useful summer tool, see our guide to frozen dog treats as the perfect summer snack.

Heatstroke vs Other Summer Illnesses

Not every off day in summer is heatstroke. A dog can also pick up a mild cold, get an upset stomach from rich picnic scraps, or simply be tired from heat without crossing into true heatstroke. The deciding factors for heatstroke are the combination of heat exposure plus the specific signs above: frantic panting, brick-red gums, drool, wobbliness, and a hot body. If your dog seems under the weather but has not been overheated, the cause is more likely something else. Our piece on whether dogs can catch a cold walks through how to tell ordinary sniffles apart from something that needs a vet.

The Cooper's Treats Approach

We are a frozen treat company, so we will be honest about what a Pupsicle is and is not. It is not a treatment for heatstroke, that is a veterinary emergency, full stop. What a frozen treat is good for is the prevention side: a low-calorie, real-meat way to cool a dog down a little and keep them calm and shaded on a hot day instead of overdoing it. Stock the freezer with the summer bundle so you always have a cold reward on hand when you are trying to talk an excited dog out of running laps in 95 degree heat.

If you ever suspect heatstroke, do not wait and watch. Start cooling and get to a vet immediately. A dog that looks recovered can still have internal damage that turns serious hours later.