Dog Heat Exhaustion and Heatstroke Signs: What to Do

“Heat exhaustion” and heatstroke

People often search for “heat exhaustion,” but veterinary sources commonly use heat-related illness for the range of problems caused by exertion or environmental heat. Heatstroke is the life-threatening end of that range and can damage the brain, gut, kidneys, liver, heart, and blood-clotting system.

You cannot safely diagnose the stage from one symptom or one temperature reading at home. The practical question is whether the dog is recovering promptly after activity stops. A dog whose panting, behavior, or coordination is worsening needs urgent veterinary help.

A rectal temperature may help a veterinary team, but taking it should never delay cooling or put you at risk of being bitten. A concerning temperature can support the decision to seek care, but a reading that has started to fall does not rule out heatstroke or internal injury. Treat the dog’s overall condition and the veterinarian’s advice as more important than reaching a particular number.

Early warning signs versus emergency signs

The Cornell University College of Veterinary Medicine lists persistent excessive panting and drooling, breathing difficulty, bloody diarrhea, vomiting, weakness, confusion, seizures, and collapse as reasons for immediate veterinary care.

What to do in the first few minutes

1. Stop the activity. Do not finish the route. Move off hot pavement and arrange transport.
2. Move somewhere cool. Use deep shade, air conditioning, or a well-ventilated area.
3. Cool first. The Royal Veterinary College recommends starting cooling before transport. For a conscious, otherwise healthy dog with exertional heat illness, cold-water immersion can be effective when it can be done safely. Keep the head above water and do not interfere with breathing.
4. Use water plus airflow for vulnerable dogs. For an older, unconscious, or medically vulnerable dog—or when immersion is not safe—pour or spray water cooler than the dog over the body and combine it with a fan, breeze, or air conditioning. Do not cover the dog with wet towels that warm up and trap heat.
5. Offer water only when safe. Let an alert dog take small sips. Never force water into the mouth of a weak, confused, vomiting, or unconscious dog.
6. Call a veterinarian. Describe the symptoms, weather and exercise, cooling already started, and temperature only if it was obtained safely. Transport in a pre-cooled vehicle with airflow.

Do not use rubbing alcohol. Do not delay cooling while looking for a thermometer, and do not assume improvement means internal injury is impossible. Follow the veterinarian’s instructions about when to slow or stop active cooling.

Why dogs overheat on walks

Dogs rely heavily on panting, which is less effective in humid, still air. Direct sun, hot pavement, running, pulling, hills, and poor heat acclimation add risk. A short outing can be enough when several factors combine.

Flat-faced dogs, seniors, puppies, overweight dogs, thick- or dark-coated dogs, large dogs, and dogs with heart, airway, breathing, or endocrine problems need a more conservative plan. Ask your veterinarian about individual exercise limits rather than relying on a universal temperature cutoff.

After a concerning heat episode

Even if your dog appears better, a veterinarian may recommend an examination because complications can be delayed. Keep the rest of the day quiet and watch for renewed panting at rest, weakness, refusal to eat, vomiting, diarrhea, coughing, breathing difficulty, wobbliness, dark or bloody stool, or abnormal gum color.

Prevent heat-related illness

• Use the heat, humidity, pavement, exercise, and individual-dog checklist.
• Walk during cooler hours and choose shade and grass.
• Carry water and keep the pace and route shorter than usual.
• Avoid running, biking, fetch, and long hikes in heat or humidity.
• Build heat acclimation gradually and stop at the first behavior change.