Heatstroke is a life-threatening emergency. Seek veterinary attention immediately.
Heatstroke involves potentially life-threatening elevations in body temperature (hyperthermia). Heatstroke is an emergency. In dogs, it can lead to rapid multi-organ failure and has a high mortality rate .
Signs of heatstroke
Signs of heatstroke in dogs may include: constant panting, rapid breathing and heart rate, pale or red gums, drooling, vomiting, diarrhoea, dizziness, weakness, lethargy, confusion, muscle tremors, seizures, little to no urination, and collapse.
Risk factors for heatstroke
Heatstroke occurs when an animal is unable to maintain their normal body temperature. Some risk factors include [2, 3]:
- Body weight – Overweight animals overheat faster and have a limited capacity for cooling.
- Breed – Purebred dogs are more likely to have exaggerated physical features that limit their ability to maintain their normal body temperature, especially flat- faced breeds which have a reduced capacity to cool down by panting.
- Sex – Male dogs are more likely to develop heatstroke after exercise.
- Age – Very young animals have a limited ability to regulate their body temperature, and very old animals are more likely to have health conditions that limit their capacity for cooling.
- Environment – Heatstroke is a greater risk when there is insufficient air flow, lack of shade and water, and in warm/hot, humid environments but heatstroke can develop even in cooler weather if other risk factors are present (e.g., flat-faced breeds, excessive exercise, deprived of shade and water, locked in cars).
- Exercise – Exercise can result in heatstroke if heat generation exceeds heat loss (e.g., excessive exercise, exercise in hot weather, lack of shade, insufficient rest, insufficient water)
- Transport – Transport can involve multiple risk factors for heatstroke including insufficient air flow, lack of shade and water, and a warm/hot environment.
- Climate change – The risk of heatstroke is increasing with climate change as temperatures rise, and heatwaves become more frequent and prolonged.
Minimising the risk of heatstroke
Minimising the risk of heatstroke involves addressing the risk factors. You can help prevent heatstroke via weight management, avoiding high risk breeds with exaggerated features like flat faces, providing sufficient water, avoiding hot surfaces (e.g. sand, concrete), exercising with your dog at coolest times of day and avoiding the hottest times of the day, and giving access to a cool, shaded area with good ventilation at all times.
There is evidence that in warm weather the ground temperatures can be unsafe for dogs, not just on surfaces like concrete or asphalt but even on bare ground and grass (especially brown grass) in predominantly sunny and dry spots . If the ground is too hot and dogs cannot retreat to a shady and cooler place, the hot ground can cause additional warming, on top of already warm air temperatures. In severe cases, hot ground can also cause skin damage.
Never leave your dog in a vehicle. Even on an overcast day with the windows down, dogs can still overheat and die in a short time.
First-aid for heatstroke
If you suspect your dog is suffering from heatstroke, start emergency first aid. Try to cool your dog down by applying room-temperature or cool water to their fur/skin. To maximise heat loss, keep the environment cool (e.g. fan, air-conditioning). Seek veterinary attention immediately.
 Bruchim, Y., Horowitz, M., & Aroch, I. (2017). Pathophysiology of heatstroke in dogs–revisited. In Temperature (Vol. 4, Issue 4, pp. 356–370). Routledge. https://doi.org/10.1080/23328940.2017.1367457
 Hall, E. J., Carter, A. J., Chico, G., Bradbury, J., Gentle, L. K., Barfield, D., & O’neill, D. G. (2022). Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs—A VetCompass Study. Veterinary Sciences, 9(5). https://doi.org/10.3390/vetsci9050231
 Hall, E. J., Carter, A. J., & O’Neill, D. G. (2020). Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016. Scientific Reports, 10(1). https://doi.org/10.1038/s41598-020-66015-8
 Hudak P (2021) Lawns Too Hot for Dogs in Warm Weather. Journal of Applied Animal Welfare Science 1–6