Last Updated: 25/08/2026
Heatstroke in Dogs: A Vet's Guide to Signs, Treatment & Prevention
Summer fun can turn dangerous if your dog overheats. Learn to recognise the signs of heatstroke, a medical emergency that can be fatal. Our vet explains how to prevent it and what to do if it happens, ensuring your dog stays safe during the hot months.
Author: Dr Brittany Ward BVSc
Reading Time: 5 minutes - short read
Summer days are perfect for making memories with our dogs, from fun at the beach to festive family gatherings. However, it's vital to remember that our canine friends are more vulnerable to the heat than we are. A fun day out can quickly become dangerous if a dog overheats, leading to heatstroke, a serious and life-threatening medical emergency.
This guide covers how to recognise heatstroke, what to do if it happens, and how to help prevent it. For what happens once you're at the clinic, see our companion guide: How Vets Treat Heatstroke in Dogs.
For a full rundown of warm-weather risks beyond heatstroke, from ticks to sunburn, see our Summer Ready guide.
What is heatstroke?
Heatstroke, also known as hyperthermia, is a dangerous increase in a dog's body temperature above the normal range. Understanding the basics is key to prevention.
- Normal body temperature: A healthy dog's temperature is typically between 38.0C and 39.0C.
- When it becomes dangerous: A body temperature exceeding 41C is a critical emergency. At this point, organ failure can begin, and neurological symptoms may appear.
- How dogs cool down: Unlike humans who sweat efficiently, dogs primarily cool themselves by panting. They have only a small number of sweat glands located in their paw pads.
- The limits of panting: Panting is a form of evaporative cooling, but it becomes less effective as humidity rises. In high humidity (over 80%), panting can actually generate more heat than it removes. This process also leads to water loss, which can cause dehydration.
- A rapid emergency: Heatstroke can progress incredibly quickly and may become fatal in as little as 15 minutes. Every second counts; the longer a dog's temperature remains elevated, the higher the risk of severe, long-term health problems or death.
Hyperthermia is classified into three categories depending on its severity:
Heat Stress
- Often goes unnoticed
- Increased thirst and panting
- Dogs are still aware and able to move around
Heat Exhaustion
- More severe form of heat stress
- Dogs have significantly increased thirst, heavy panting, weakness and may collapse
- Dogs are mentally aware, but often too lethargic to respond or move around
Heatstroke
- Defined by a body temperature higher than 41C
- Organs will begin to fail and neurological dysfunction can occur
- Characterised by more severe symptoms
- Requires immediate cooling and veterinary treatment
What are the signs of heatstroke in dogs?
It is important to recognise heatstroke quickly to ensure the best outcome as it can quickly progress to death. There are a number of signs and symptoms that you can look for in your dog.
Early signs of heatstroke can include:
- Increased body temperature
- Heavy panting or difficulty breathing
- Restlessness, agitation or shade seeking
- Excessive drooling
- Change in gum colour to bright red or bluish-purple
As the condition worsens, signs can progress to include:
- Vomiting
- Diarrhoea (may include blood)
- Increased heart rate
- Lethargy or collapse
- Dizziness - may present as a staggering gait
- Confusion
- Muscle tremors
- Seizures
- Becoming unresponsive or unconscious
A common mistake we see in clinic: owners assume laboured panting after a walk is just their dog being a bit puffed, when panting that doesn't settle within 10 minutes of rest and shade is often the first real warning sign of heat stress escalating.
What should I do if my dog has heatstroke?
Heatstroke can be fatal and is considered a medical emergency! Your dog requires immediate attention and the sooner they get to a vet, the better their prognosis. However, you will need to start the cooling process before transporting your dog.
Immediate first aid
If your dog is showing any of the above signs of hyperthermia, follow the below steps to help your dog start cooling down on the way to the vet clinic.
- Remove your dog from the source of the heat and move to somewhere cool.
- Use a bucket or hose to pour water over them, avoiding their face. This water should be cooler than your dog, but NOT ice-cold.
- Place them in front of a breeze, fan or air conditioning (at room temperature). The air conditioning in your car or an open car window are great options. Air flow combined with wetting them down promotes evaporative cooling.
- Offer them water, ideally small sips.
- Call your vet to let them know you are coming in and transport your dog to the clinic, continuing the cooling methods on the way.
Heatstroke DONT'S
- NEVER use ice or ice water to cool your dog down. Ice and cold water will cause the blood vessels to constrict, retaining heat. Room temperature or cool water is best. If you are using air conditioning, this should also be kept at a comfortable, ambient temperature, such as 24-26C to avoid cooling too quickly. Cooling too quickly can cause Hypothermia.
- NEVER place a wet towel or cloth over your dog. These will absorb the heat from their body and create humidity, further raising your dog's temperature.
Even if your dog seems to perk up once you start cooling them, always continue on to the vet. Internal organ damage and clotting problems can develop hours later, even when your dog looks like they have recovered.
How can I prevent heatstroke in my dog?
Prevention comes down to keeping your dog cool: shade, water, avoiding enclosed spaces and cars and hot pavement, and cooling gear like mats or vests on the worst days.
The question our vet team gets asked most: is it still safe to walk a dog in the early morning? Our rule of thumb: if the pavement's too hot for your palm after seven seconds, it's too hot for their paws.
For the full prevention playbook, see our guide on How to Keep Your Dog Cool in Hot Weather.
Heatstroke FAQs
References
Heat Stroke in Dogs - VCA Hospitals - https://vcahospitals.com/know-your-pet/heat-stroke-in-dogs
Heat Stroke in Dogs - Animal Emergency Services - https://animalemergencyservice.com.au/blog/heat-stroke-in-dogs/
Heatstroke in Dogs and Cats - Royal Veterinary College - https://www.rvc.ac.uk/small-animal-vet/teaching-and-research/fact-files/heatstroke-in-dogs-and-cats
Heatstroke in Dogs - PetMD - https://www.petmd.com/dog/conditions/systemic/heatstroke-dogs
Today's Technician Heatstroke in Dogs - https://todaysveterinarypractice.com/emergency-medicine-critical-care/todays-technician-heatstroke-in-dogs/
What You Need to Know About Heatstroke in Dogs - https://www.sydneyvetspecialists.com.au/what-you-need-to-know-about-heat-stroke-in-dogs/
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue 25 Aug 2026
Edited by Dr Gillian Hill BVSc (Hons)Dr Brittany Ward BVSc
Veterinarian
Dr. Brittany graduated from James Cook University in 2019 with a Bachelor of Veterinary Science and started working in her home town in the Wide Bay-Burnett Region. She has always been excited about working in the veterinary industry, but over the last few years has grown especially fond of dog behaviour and training, surgery and orthopaedic disease.
