Why Dogs Pant Heavily

1 Normal Panting and Cooling

Unlike most animals, dogs have very few sweat glands — only on the nose tip and paw pads — so sweating alone cannot cool them. They dissipate heat by breathing faster and panting with the tongue out.

When the body makes heat quickly or struggles to release it — during excitement, fear, exercise, or high temperatures — a dog’s breathing rate rises noticeably, sometimes with the mouth open and tongue out. This is not sickness; let the dog rest quietly in a cool, shaded spot or use simple cooling measures and the breathing soon slows.

2 When Panting Signals Illness

If a dog pants like this in the middle of winter with no strenuous exercise, suspect illness: a high fever, a respiratory disease, encephalitis, a painful condition, or tetanus. Seek prompt diagnosis and treatment.

3 Heat and Heatstroke

Because dogs cannot cool through their skin, they stick out the tongue and pant in summer heat. Avoid leaving a dog in poorly ventilated spaces or under strong sun for long — past a point, even panting and tongue-drooling will not bring the temperature down.

4 Fever and When to Call the Vet

A fever is generally considered present above 40°C (104°F), though a slightly elevated temperature is not always illness — a dog’s temperature can swing 1–2°C (1.8–3.6°F) across the day with mood, activity, or environment.

Pathological panting and persistent fever usually come from infection. Heatstroke, low blood calcium, and cancer can also keep the temperature high. If the dog has a fever with lethargy, a miserable expression, poor appetite, rapid breathing, and a fast heartbeat, see a vet immediately.