Is Your Dog Too Hot? Warning Signs of Dangerous Heatstroke

Sep 11, 2026

A hot day can be uncomfortable for your dog, but dog heat stroke is much more serious than simply feeling warm. A dog that is panting heavily on a hot day may simply be trying to cool down, but persistent or worsening signs of overheating can quickly become heatstroke, which is a life-threatening veterinary emergency. Dogs cannot cool themselves as efficiently as people do. They rely mainly on panting and releasing heat through their paws, which means they can become dangerously overheated, particularly during hot or humid weather, strenuous exercise or when left somewhere without adequate ventilation. Some dogs are also at greater risk, including flat-faced breeds, overweight dogs, older dogs, very young dogs and those with heart or breathing problems.

What Is Dog Heat Stroke?

Dog heatstroke is a life-threatening emergency that occurs when a dog’s body temperature rises beyond its ability to cool itself. Without prompt treatment, severe heatstroke can cause dehydration, organ damage, collapse and potentially death.

Dogs can develop heatstroke surprisingly quickly, particularly during hot or humid weather. It is not limited to extreme outdoor temperatures. Hot cars, poor ventilation, strenuous exercise, dehydration and exposure to hot environments can all cause a dog to overheat.

Some dogs are also more vulnerable than others, including:

  • Flat-faced (brachycephalic) breeds, such as Pugs, French Bulldogs and Bulldogs, which can have difficulty cooling themselves through panting
  • Puppies and older dogs, which may have less ability to regulate their body temperature
  • Overweight dogs, which can overheat more easily
  • Dogs with thick or long coats, which can retain more heat
  • Dogs with heart or respiratory conditions, which may have more difficulty coping with heat and increased breathing demands
  • Dehydrated dogs, which have a reduced ability to cool themselves
  • Dogs exercising heavily in hot or humid conditions, particularly during the warmer parts of the day

The RSPCA notes that brachycephalic dogs have a particularly high risk because their shortened airways can make it harder to cool themselves through panting.

Can a Dog Recover From Heatstroke?

Yes, some dogs can make a full recovery from heatstroke, particularly when cooling and veterinary treatment begin quickly. However, severe heatstroke can cause serious internal damage and may be life-threatening.

A dog’s chances of recovery depend on several factors, including how high their body temperature became, how long they remained overheated, how quickly treatment started and whether complications developed. Heatstroke can affect multiple organs, including the kidneys, liver, gastrointestinal tract, heart, brain and blood-clotting system.

Importantly, a dog appearing better after being cooled does not always mean they have fully recovered. Some complications may develop after the initial overheating has been treated, which is why veterinary monitoring can be important even when your dog seems more comfortable.

This is why a dog that has experienced suspected heatstroke should be assessed by a veterinarian, even if they seem better after cooling.

How to Tell If Your Dog Is Too Hot

Panting is normal after exercise or on a warm day. But if your dog is panting heavily and cannot settle, cool down or breathe comfortably, they may be overheating.

Heatstroke can become life-threatening quickly. Watch for these warning signs:

Excessive or relentless panting

Heavy panting that does not ease after your dog stops exercising and moves somewhere cool is a warning sign.

Excessive drooling

Your dog may drool much more than usual, with saliva becoming thick or sticky.

Red, pale or abnormal gums

Gums may appear unusually red, pale or otherwise abnormal. Changes in gum colour should be taken seriously, particularly when combined with other signs.

Restlessness or agitation

An overheated dog may seem anxious, unsettled or unable to get comfortable.

Weakness or lethargy

As heatstroke progresses, your dog may become weak, lethargic or reluctant to stand or walk.

Difficulty breathing

Rapid, laboured or increasingly difficult breathing is an emergency warning sign.

Vomiting or diarrhoea

Heatstroke can affect the digestive system and may cause vomiting or diarrhoea. Severe cases may involve bloody diarrhoea.

Staggering, confusion or disorientation

Neurological signs are particularly concerning. Your dog may become uncoordinated, confused or have difficulty walking normally.

Muscle tremors or seizures

Trembling, muscle twitching or seizures indicate severe illness and require immediate veterinary treatment.

Collapse or unconsciousness

If your dog collapses, becomes unresponsive or loses consciousness, they need emergency veterinary care immediately.

What Should You Do If You Suspect Heatstroke?

Treat suspected heatstroke in dogs as a veterinary emergency. Heatstroke can cause serious complications, including organ damage, and can become life-threatening quickly. Move your dog somewhere cool, away from direct sunlight or the hot environment and into a cool, well-ventilated area. Start cooling them with cool or room-temperature water. Apply cool or room-temperature water to their coat or skin and use a fan or air conditioning to help with cooling. Avoid using ice or extremely cold water, as this can interfere with safe cooling. If your dog is alert and able to drink, you can offer small amounts of fresh water. Do not force water into their mouth, particularly if they are weak, confused or struggling to swallow. Contact your vet immediately. Cooling your dog is first aid, not a substitute for veterinary treatment. Even if your dog appears to recover after cooling, heatstroke can cause internal damage that is not immediately obvious. Dogs may require monitoring, fluids and treatment for complications following significant overheating.

Never Leave Your Dog in a Parked Car

Never leave your dog alone in a parked car, even if the weather feels mild, the windows are partly open or the vehicle is parked in the shade. A car can become dangerously hot in a short time, putting your dog at risk of heatstroke, a life-threatening emergency. Opening the windows or parking in the shade does not make a parked car safe for a dog. Dogs can develop potentially fatal heat stress quickly, and you should not assume that a short stop is harmless. If you cannot take your dog with you and you need to leave the car, leave your dog at home or take them somewhere cool, shaded and well ventilated instead.

The Best Protection Against Dog Heat Stroke Is Prevention

The best way to protect your dog from heat stroke is to prevent overheating before it starts. On hot or humid days, even normal exercise can become dangerous, particularly for flat-faced breeds, older dogs, overweight dogs and dogs with heart or breathing problems.

When temperatures are particularly high, remember that your dog does not need to go for their usual walk. Indoor enrichment, gentle training games and quiet activities can provide mental stimulation while keeping them safely out of the heat.

Keep plenty of fresh water available, make sure your dog has a cool and shaded place to rest, and avoid exercising during the hottest part of the day. It is also worth checking the pavement before heading out, as hot surfaces can burn your dog’s paw pads.
Most importantly, trust your instincts. If your dog seems unusually tired, is panting excessively, appears weak or unsteady, or you are simply worried that they may be overheating, don’t wait for their symptoms to get worse.

If you’re concerned about your dog’s health in hot weather, the team at Rossmore Vet Centre is always happy to help.