Heat Stroke in Dogs: The Early Signs Burlington Owners Miss

A caller reaches the front desk on a bright afternoon in late July. Her retriever went quiet on the walk back from the waterfront, and now he won’t settle on the kitchen floor.

She keeps saying he’s “just tired.” That word, tired, is the one our Burlington team worries about most.

The earliest signs of heat trouble rarely look like an emergency. They look like a good dog slowing down on a warm day.

According to Cornell’s Riney Canine Health Center, heatstroke is a life-threatening emergency that begins when a dog’s temperature reaches 105°F or higher, well above the normal range of 100.5 to 102.5°F. The early indicators Cornell names include heavy panting, drooling, weakness, and collapse.

If this is happening right now, don’t wait to see if it passes — call us at (905) 336-4002. Outside our hours, head to your nearest emergency hospital using our after-hours care guidance.

Heat stroke moves fast, and it hides in plain sight. These are the questions we field most once the weather turns in Burlington.

What are the early signs of heat stroke that Burlington owners miss?

The missed signs are the quiet ones. According to Cornell’s Riney Canine Health Center, indicators include heavy panting, drooling, vomiting, diarrhea, weakness, and collapse, while the AVMA adds anxiousness, restlessness, unsteadiness, and abnormal gum or tongue colour as signs that need emergency care right away.

Most people picture a dog in obvious distress. In reality the first stage looks a lot like ordinary summer fatigue.

A dog panting harder than the walk should warrant, or one who drops behind on the leash and lies down in the shade. These are the moments the Cornell and AVMA guidance is pointing at.

The Ontario Veterinary Medical Association describes the same picture: excessive panting, muscle twitching, an anxious or dazed look, vomiting, weakness, increased drooling, and diarrhea. The OVMA is blunt about what comes next, saying a pet with these signs needs to be seen by a veterinarian immediately.

Colour is the tell people forget to check. The AVMA lists abnormal gum and tongue colour among its warning signs, so it helps to know what your dog’s healthy gums look like on a normal day.

At what temperature does a dog get heat stroke?

According to Cornell’s Riney Canine Health Center, a healthy dog’s temperature runs between 100.5 and 102.5°F, and heatstroke sets in at 105°F or higher. Cornell also notes that prolonged high temperatures damage every organ in the body, and that prognosis depends on how high the temperature climbs and how long it stays there.

We won’t put a diagnostic number on your dog from a keyboard, and taking a temperature at home during a crisis isn’t the priority. Getting to a vet is.

If you’re seeing the signs above, treat it as an emergency and call us rather than trying to confirm a reading yourself. Because harm tracks with how hot a dog gets and how long they stay hot, these calls go straight through to our critical care team.

Which dogs are most at risk on a Halton summer day?

According to Cornell, short-muzzled (brachycephalic) breeds, along with older or overweight dogs, carry higher risk. A large UK primary-care study by Hall and colleagues found brachycephalic dogs had roughly double the odds of heat-related illness, and the OVMA adds that thick-coated and long-haired dogs are more susceptible too.

“Brachycephalic” simply means short-faced — think of the flat-nosed breeds like bulldogs and pugs. The research puts real numbers behind that risk.

Weight is the risk factor owners have the most control over. Because the AVMA flags overweight pets specifically, a heavier dog heading into summer is a good reason for a conversation about nutrition and weight management.

Age deserves the same care. A senior dog who cruised through past summers may not have the same reserve this year, which is easy to check at a routine wellness visit.

If your dog sits in more than one row of that table, plan the day around the heat rather than the walk you’d normally take.

Can a dog get heat stroke from a summer walk, not just a hot car?

Yes, and it’s actually the bigger risk. In the VetCompass study by Hall and colleagues, 74.2% of canine heat-related illness cases were triggered by exertion, 12.9% by hot environments, and only 5.2% by confinement in a vehicle. The researchers’ message was direct: dogs don’t die just in hot cars.

The hot-car warning is real and it matters. But it has quietly convinced many owners that never leaving the dog in the car covers the whole risk.

The data says otherwise. Far more dogs get into trouble on a walk, run, or hike than in a parked vehicle.

We see this every summer in Burlington. A well-meaning owner takes the usual midday loop, the dog keeps going, and the trouble shows up on the way home.

The AVMA’s advice fits exactly: skip walks and runs during the hottest parts of the day, and always give your dog fresh water and access to shade. In Halton that often means shifting real exercise to the cooler edges of the day.

What should I do first if my dog is overheating?

According to Cornell’s Riney Canine Health Center, first aid on the way to the vet is to wet the dog with cool water and place them directly in front of the car’s air conditioning. Cornell also warns never to leave a dog in a car unattended.

Move first, cool second, drive third. That order keeps things calm.

Get your dog out of the heat and into shade or air conditioning right away. Then start wetting them with cool water while you head for care, and call us on the way at (905) 336-4002.

The reason we don’t want you cooling at home and “seeing how it goes” traces back to Cornell’s point about organ damage. Because harm builds the longer a dog stays overheated, the safest place for a dog past the early signs is on the way to a clinic.

If it’s outside our hours, go straight to the nearest emergency hospital using our after-hours care guidance.

Should I use cold water or ice to cool my dog down?

Reach for cool water. Cornell’s Riney Canine Health Center recommends wetting an overheating dog with cool water and positioning them in front of the car’s air conditioning on the way to the hospital. Cornell frames this cooling as first aid while you get to a veterinarian, not a replacement for the exam.

Owners often ask whether ice would work faster. What Cornell’s published guidance actually names is cool water, paired with getting to a hospital, so that’s what we point people to.

How much cooling, how fast, and for how long depends on the individual dog and how far along they are. That’s a judgment call for the exam room, and exactly what to ask us on the phone while you drive in.

When in doubt, wet your dog with cool water, aim the air conditioning at them, and call (905) 336-4002.

Is it illegal to leave a dog in a hot car in Burlington?

Yes. The City of Burlington warns that temperatures in parked cars can turn deadly within minutes, and that leaving a pet unattended in a hot vehicle may bring charges under Ontario’s PAWS Act or the Criminal Code of Canada. Report a pet in distress to Halton Regional Police (905-825-4777) or Burlington Animal Services (905-335-7777).

The OVMA puts it plainly, warning never to leave a pet alone in a vehicle. Temperatures inside can skyrocket in a short time even with the windows rolled down.

If you find a dog shut in a car on a hot Burlington day, the City’s guidance is to report it to the numbers above rather than wait and hope. Halton Region Public Health has declared Extended Heat Warnings during multi-day heat events in our area.

There’s a local upside worth knowing, too. During a declared Heat Warning, Burlington Public Library branches serve as official cooling centres where pets may come inside with their owners.

This article is educational and isn’t veterinary advice or a substitute for an exam. If you’re worried about your pet right now, call us at (905) 336-4002 or your nearest emergency veterinary hospital.

Summer in Burlington is short, and most of it is meant to be spent outside with your dog. If you’re not sure whether your dog is built for the heat, or you’d like a plan for the hottest weeks, our team on Brant Street is glad to help.

Request an appointment

Frequently asked questions

How quickly can a dog get heat stroke?

Faster than most owners expect. The City of Burlington warns that a parked car can turn deadly in a matter of minutes, and Cornell notes that damage builds the longer a dog stays overheated. There’s no safe waiting period once you see heavy panting, drooling, weakness, or collapse, so call us at (905) 336-4002 straight away.

What are the official warning signs I should watch for?

The AVMA lists seven that need emergency care: anxiousness, excessive panting, restlessness, excessive drooling, unsteadiness, abnormal gum or tongue colour, and collapse. The OVMA adds muscle twitching and an anxious or dazed look. If your dog shows any of these on a warm Halton day, treat it as urgent and head for care.

How hot does a parked car really get?

Hot enough to be lethal quickly. The City of Burlington states that temperatures in parked cars can turn deadly in a matter of minutes, and the OVMA warns that a car’s interior can skyrocket in a short time even with the windows rolled down. Cracking a window doesn’t make it safe, so never leave your dog inside.

Can cats get heat stroke too?

Yes. The Ontario Veterinary Medical Association notes that cats can also suffer heat stroke, alongside the dogs this article focuses on. The same principles apply: fresh water, shade, cool indoor space on hot days, and never leaving them in a vehicle. If your cat seems overheated or distressed, call our Burlington team.

Where can I cool off with my dog during a Halton heat warning?

During a declared Heat Warning, Burlington Public Library branches act as official cooling centres, and the City notes pets may come inside with their owners in a designated area. A Heat Warning is issued when temperatures are expected to reach at least 31°C with overnight lows above 20°C for two days, or the humidex hits 40 for two days.

My dog seemed fine after overheating. Do I still need a vet?

It’s worth a call. Cornell’s Riney Canine Health Center explains that prolonged high temperatures can damage every organ in the body, and some effects aren’t obvious right away. A dog who bounced back may still benefit from a check, so phone us at (905) 336-4002 and we’ll help you decide.

Sources

Veterinary medicine and science

1. Cornell University College of Veterinary Medicine, Riney Canine Health Center: Heatstroke: A Medical Emergency. https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information/heatstroke-medical-emergency
2. Hall EJ, et al. Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care. Scientific Reports (VetCompass, RVC), via NCBI/PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC7303136/
3. Hall EJ, et al. “Dogs Don’t Die Just in Hot Cars”: Exertional Heat-Related Illness (VetCompass), via PubMed/NCBI. https://pubmed.ncbi.nlm.nih.gov/32751913/

Provincial and national veterinary bodies

1. American Veterinary Medical Association (AVMA): Warm Weather Pet Safety. https://www.avma.org/resources-tools/pet-owners/petcare/warm-weather-pet-safety
2. Ontario Veterinary Medical Association (OVMA): Pet Safety Tips. https://www.ovma.org/petcare/pet-safety-tips

Burlington and Halton public health and bylaws

1. City of Burlington: Animal Control By-law (hot vehicles, reporting contacts). https://www.burlington.ca/en/by-laws-and-animal-services/animal-control-by-law.aspx
2. Take Action Burlington: Be Prepared for Extreme Heat (Heat Warning criteria, cooling centres). https://takeactionburlington.ca/2026/07/07/be-prepared-extreme-heat/
3. Halton Region Public Health: Extended Heat Warning media release. https://www.halton.ca/news/media-releases/2026/extended-heat-warning-issued-for-halton-region-starting-june-30-2026