Glossary

Heatstroke

A dangerous rise in body temperature, from about 104 F up, when a dog cannot cool itself, and a true emergency.

Also called: heat stroke, hyperthermia, overheating, dog in hot car

Heatstroke happens when a dog's body heat climbs faster than panting can shed it. A normal dog temperature is about 101 to 102.5 F, and a reading of about 104 F or higher is a danger sign. Signs are heavy panting, drooling, bright red or pale gums, vomiting, wobbling, glassy eyes and collapse, and the organs can be damaged.

Hot cars are the best-known cause, and even a cracked window does not make parking in warm weather safe. Exercise in hot, humid weather, hot pavement and a lack of shade and water also cause it. Flat-faced breeds, overweight, thick-coated and older dogs are at higher risk.

Move the dog out of the heat and call a veterinarian immediately, because a dog that looks recovered can still have internal damage. Do not use ice-cold water, as vets give specific cooling advice.

Last reviewed November 8, 2026

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Related terms

Brachycephalic obstructive airway syndrome A set of airway abnormalities in flat-faced breeds that make breathing hard, causing noisy breathing, poor heat tolerance and collapse. Obesity Excess body fat that shortens lives and raises the risk of arthritis, diabetes and other disease; it is the most common nutrition problem in pet dogs.