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Safety · Dogs

Heatstroke in dogs: signs, risk and prevention

Heatstroke is a potentially fatal emergency. It can develop during exercise, exposure to hot environments or whenever a dog cannot move away from a heat source. It is not limited to extremely hot days.

The Amaeru dog moves from the sun toward shade and a water bowl
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Summary

The important points, first

  • Excessive panting and drooling, breathing difficulty, weakness, confusion or collapse require immediate care.
  • Brachycephalic, older and overweight dogs and those with heart or respiratory disease are at higher risk.
  • Stop activity, move the dog somewhere cool and begin controlled cooling while contacting a veterinarian.
  • Never leave a dog in a vehicle, even for a few minutes.
01

How heat-related illness develops

Cornell describes heatstroke as a dangerous rise in body temperature after prolonged heat or humidity exposure or strenuous exercise. Dogs lose heat mainly by panting; high humidity, poor airflow and exercise can reduce how effectively this works.

A VetCompass study of UK veterinary records found that most events were triggered by exercise and that the median outdoor temperature on event days was 16.9 °C: it does not take a scorching day. Severe illness was more likely when dogs could not escape the heat source, such as when shut in a vehicle.12

02

Signs and more vulnerable dogs

Heavy panting, seeking shade, reluctance to move and drooling can accompany overheating. Breathing difficulty, vomiting, diarrhoea including blood, weakness, altered mentation, seizures and collapse indicate a more serious situation.

Any dog can be affected, but Cornell calls for extra care with brachycephalic, older and overweight dogs, dogs with heart or respiratory disease and dogs with thick or dark coats. In VetCompass data risk was also higher in some breeds, such as Chow Chow, Bulldog and French Bulldog, and in dogs heavier than their breed average; the risk of death was higher in older and brachycephalic dogs.123

03

Prevention and first actions

Plan walks for cooler periods, reduce duration and intensity in heat or humidity, choose shade and water, and stop at the first warning signs. Do not use human perception of temperature alone to judge safe exertion for a dog.

If heatstroke is possible, move the dog to a cool place, use cool—not ice-cold—water and airflow, and contact a veterinary clinic immediately. Initial cooling does not replace clinical assessment because complications can continue after apparent improvement.12

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Sources and checks

Numbers in the text lead to the exact source. Commercial blogs and social posts are not used as evidence.

  1. 1
    University veterinary centre

    Summer heat safety tips for dogs

    Cornell University College of Veterinary Medicine · Signs, risk factors, initial cooling and prevention of heatstroke.

    Link checked on 15 Sept 2026
  2. 2
    Peer-reviewed research article

    Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs

    Veterinary Sciences (2022), VetCompass · PubMed PMID 35622759 · Study of factors associated with severe and fatal heat-related illness in dogs.

    Link checked on 15 Sept 2026
  3. 3
    Peer-reviewed research article

    Incidence and risk factors for heat-related illness in UK dogs

    Scientific Reports · PubMed PMID 32555323 · Epidemiological data on incidence and risk factors for heat-related illness.

    Link checked on 15 Sept 2026

Heatstroke is an emergency. This guide does not replace veterinary instructions or immediate transport to a clinic.

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