Signs your dog is overheating include heavy panting that doesn’t ease, excessive drool, weakness or collapse, vomiting, bright red gums, and a dazed or unsteady appearance. These escalate quickly, and knowing what you’re looking at makes the difference between catching it early and watching it turn dangerous. What follows are the clear indicators, the timeline of how they appear, and what to do the moment you recognise them.
I’ve stood in a park on a hot day and watched dogs run themselves into trouble faster than their owners realised what was happening. The panting looked normal at first. Then it didn’t. So here are some signs of overheating to be aware of.
Early Signs Before It Becomes Serious
The first signs are easy to miss because they look like normal tired-dog behaviour. Heavy panting is expected after a run or on a warm day. What matters is whether it calms down after a few minutes of rest or continues without easing.
- Panting that stays rapid and shallow: If your dog has stopped moving but the panting remains fast and doesn’t slow, that’s the first real signal. Normal panting settles. Overheating panting doesn’t.
- Drooling more than usual: Thick, ropey drool rather than the usual amount. Some dogs drool naturally, but an increase beyond their normal pattern is worth noting.
- Restlessness or reluctance to settle: They might pace, refuse to lie down, or seem uncomfortable even in shade. This restlessness often appears before the more obvious physical signs.
- Bright red or dark gums and tongue: Gums should be pink. Bright red, purple, or unusually dark colour means they’re struggling to regulate temperature.
These early signs give you a window to act before the situation worsens. I’ve caught it at this stage more than once by stopping and checking gums and panting rhythm rather than assuming they just needed a minute.
Advanced Signs That Require Immediate Action
If the early signs are missed or ignored, the condition escalates. Advanced overheating looks different. The dog stops behaving normally and starts showing clear distress.
- Weakness or stumbling: They might struggle to stand, walk unsteadily, or collapse. This happens because their body is prioritising core functions and losing coordination.
- Vomiting or diarrhoea: The digestive system shuts down under heat stress, and vomiting or loose stools can appear suddenly.
- Glazed eyes or lack of focus: They seem distant, unable to track movement, or unresponsive to their name. This is a sign that their brain is being affected.
- Seizures or collapse: At the most severe end, the dog may seize, lose consciousness, or stop moving entirely. This is life-threatening and requires emergency veterinary care immediately.
The gap between early and advanced signs can be shorter than you expect, particularly in brachycephalic breeds, older dogs, or those with thick coats. If your dog is showing any combination of the above, this is not a wait-and-see situation.
What to Do the Moment You Recognise Overheating
The goal is to cool the dog down gradually without shocking their system. Rapid cooling can cause more harm than good, so the approach needs to be controlled.
Move the dog to shade or an air-conditioned space immediately. If they’re outside and can’t walk, carry them if possible. Get them off hot pavement or grass.
Offer small amounts of cool water. Let them drink at their own pace. Do not force water down their throat, particularly if they’re dazed or unsteady, as they could choke.
Wet their chest, paws, and the back of their neck with cool water. Not ice-cold. Not a full submersion. Just enough to bring their temperature down steadily. A damp towel over their body works if you don’t have access to running water.
Do not cover them in ice or plunge them into freezing water. That can cause the blood vessels to constrict and trap heat inside rather than releasing it.
Contact your vet while you’re cooling them. Even if the dog seems to recover after a few minutes, internal damage from overheating can develop hours later. A vet check is not optional.
Which Dogs Overheat Faster
Some dogs are at higher risk from the start. Knowing whether your dog falls into one of these groups changes how cautious you need to be on warm days.
- Brachycephalic breeds: Pugs, Bulldogs, Shih Tzus, and similar flat-faced breeds cannot cool themselves efficiently through panting. They overheat faster and with less exertion than other dogs.
- Older dogs: As dogs age—and the Dog Years to Human Years Calculator can give you a sense of where your dog sits—they lose some ability to regulate temperature. What they managed fine at four might exhaust them at ten.
- Overweight dogs: Extra weight makes the body work harder to cool down. A dog carrying excess weight will overheat sooner than a lean dog doing the same activity.
- Double-coated or thick-coated breeds: Huskies, Malamutes, and similar breeds have coats designed for cold climates. They struggle in heat, particularly if they’re active during the warmest part of the day.
- Dogs with underlying health conditions: Heart problems, respiratory issues, or anything affecting circulation increases the risk significantly.
I’ve learned to adjust activity based on the dog, not the weather alone. A short walk in moderate heat can overwhelm a Bulldog while barely affecting a Labrador.
How Long It Takes and Why It Happens So Fast
Dogs don’t sweat through their skin the way humans do. They release heat primarily through panting and, to a much smaller degree, through their paw pads. When the air temperature is high or humidity is significant, panting becomes less effective.
The progression from comfortable to overheated can happen in under twenty minutes if the conditions are right. A dog left in a car on a warm day, a dog running hard in direct sun, or a dog with a flat face struggling through a walk can go from fine to in trouble faster than most people expect.
I’ve seen it happen on days that didn’t feel that hot. Mid-twenties Celsius, a bit of sun, a dog who wanted to keep playing. By the time the owner noticed the panting had changed, the dog was past the early warning stage.
When the Danger Isn’t Obvious
Overheating doesn’t only happen on the hottest days of the year. It happens in cars with the windows cracked. It happens on humid days when the temperature feels manageable but the air is heavy. It happens during fetch games that go on too long because the dog won’t stop on their own.
Some dogs will not self-regulate. They’ll keep running, keep playing, keep going until they physically can’t. Relying on the dog to stop when they’ve had enough is a mistake I made more than once before I learned to be the one who calls time.
Humidity is the hidden factor. A dog can cope better in dry heat than in sticky, humid conditions where panting does almost nothing to cool them. I’ve had to cut walks short on overcast, warm days because the air felt thick and the dog’s breathing wasn’t settling.
Practical Adjustments That Actually Help
Avoiding overheating is easier than treating it. The adjustments are straightforward, and they work if you apply them consistently.
- Walk early or late: The coolest parts of the day are before nine in the morning and after seven in the evening. Pavement temperature matters as much as air temperature-if you can’t hold your hand on the ground for five seconds, it’s too hot for paws.
- Carry water on every walk: A collapsible bowl and a bottle of water. Offer it halfway through and again at the end. Don’t wait for the dog to look thirsty.
- Limit high-energy activity on warm days: Fetch, running, or wrestling can wait. A slow walk in shade is enough. The dog might want more, but wanting and needing are different things.
- Use cooling mats or damp towels indoors: A cooling mat gives them a place to lie that doesn’t trap heat. A damp towel over their back or under their chest works if you don’t have a mat.
- Never leave a dog in a parked car: Not for two minutes. Not with the windows down. Not in the shade. The temperature inside a car rises faster than outside, and it becomes lethal quickly.
If you looking for more ideas, then check out How to Keep Your Dog Cool in Hot Weather
What Happens After Overheating
Even if a dog recovers quickly after cooling down, there can be delayed effects. Kidney damage, liver problems, and neurological issues can develop hours or even days after the initial incident. This is why a vet check is necessary even if the dog seems fine once they’ve cooled.
I’ve known dogs who seemed back to normal within an hour, only for the owner to notice lethargy, loss of appetite, or dark urine the next day. Those are signs of internal damage that wasn’t immediately obvious.
Recovery from severe overheating isn’t always complete. Some dogs are left with lasting sensitivity to heat, reduced stamina, or organ function that never fully returns to baseline. Prevention is always better than hoping for a full recovery.
What It Looks Like in Real Time
The clearest way I can describe it is this: the dog stops looking like themselves. The expression changes. The movement changes. They go from engaged to absent, from coordinated to clumsy, from panting to gasping.
The moment you feel uncertain, stop what you’re doing and check. Look at the gums. Feel the dog’s body temperature. Watch the breathing pattern. If any of it seems off, act as though it is. The cost of overreacting is low. The cost of waiting is not.
This article is for informational purposes only. For advice specific to your dog always speak to your vet.