Dog Panting in Hot Weather: Heatstroke Signs and What to Do

By Dr Duncan Houston

Your dog is panting in the sun, the pavement feels warm, and the nearest tap is somewhere down the road. Should you keep walking, find shade or head straight to a vet?

Stop exercise and move your dog somewhere cool immediately. If the panting is excessive, breathing looks difficult, or your dog is weak, distressed or unsteady, start cooling and contact a veterinarian urgently. Heat-related illness can progress quickly.

Quick Answer

Panting helps dogs cool themselves, but heavy or persistent panting in hot weather can signal dangerous overheating. There is no reliable number of minutes you can safely wait for water or before heatstroke develops. Stop activity, seek shade or air conditioning, offer drinking water if your dog is alert, and begin cooling with water if overheating is suspected. Humidity, thick coats, exercise and underlying health problems increase risk, so the weather forecast alone cannot tell you whether a walk is safe.

Is my dog just hot, or developing heatstroke?

Panting after activity can be normal. What matters is the intensity, whether it eases in a cool environment, and how your dog is behaving.

Heatstroke is a severe form of heat-related illness in which overheating can damage organs. You cannot reliably judge its severity by looking at the tongue or feeling the coat.

When is panting in hot weather an emergency?

Mild panting with normal behaviour

Mild panting, normal walking and responsiveness, and settling after rest somewhere cool may be normal cooling. Stop exertion, offer water and watch closely.

Possible heat-related illness

Heavy or continuous panting, excessive drool, seeking shade or refusing to continue can signal heat-related illness. Start cooling and contact a vet immediately.

Emergency signs

Vomiting, diarrhoea, weakness, wobbliness or obvious breathing difficulty require immediate cooling and urgent veterinary transport.

Critical emergency signs

Collapse, confusion, seizures, reduced responsiveness or bloody vomit or diarrhoea are critical warning signs. Begin cooling while someone calls the nearest emergency clinic.

Do not wait for collapse. Reluctance to walk can be an early warning, even if your dog is still standing and responsive.

What should I do right now?

If your dog appears overheated:

1. Stop exercise. Do not make them finish the walk.
2. Move out of direct sun. Choose a cool indoor space, ideally with air conditioning, or the nearest shaded, ventilated area.
3. Begin cooling immediately. Run ordinary cool or cold tap water over the body below the neck, keeping it away from the nose and mouth. Wet through the coat to the skin, including the less densely haired underside. If running water is unavailable, pour water repeatedly over the body.
4. Add airflow. Use a fan, breeze or vehicle air conditioning.
5. Offer drinking water if they are alert and swallowing normally. Let them drink voluntarily. Never pour or syringe water into their mouth.
6. Call a vet and arrange transport. If someone is with you, ask them to call while you start cooling. Continue safe cooling during the journey.

Do not wrap your dog in wet towels, which can interfere with heat loss. Do not force a weak, struggling or unconscious dog into a pool.

The Royal Veterinary College’s first-aid message is “cool first, transport second”: begin cooling before departure, then get moving promptly. It does not mean waiting at home until your dog looks normal.

Ask the vet how to judge when active cooling should stop for your dog. The cooling plan can differ when a dog has an obstructed upper airway, so a single temperature cut-off is not suitable for every situation. Do not delay cooling or veterinary care to find a thermometer, and do not try to take a temperature if doing so is unsafe. Follow the clinic’s telephone guidance during transport.

What should you tell the veterinary clinic?

Start with your location and your dog’s current signs so the team can help you plan the journey. Tell them whether your dog can stand, is responding normally or has developed noisy breathing, vomiting, diarrhoea or collapse.

Explain what your dog was doing, when the problem began, any known health conditions and what cooling you have already started. If someone else is with you, they can gather the details while you help your dog. Do not delay cooling or departure to make a video, complete a symptom checklist or reconstruct an exact timeline.

How much time do I have to find water?

There is no safe waiting period that applies to every dog. A heavily panting dog in direct sun may already be struggling to lose heat.

Drinking supports hydration, but a drink alone does not adequately treat heatstroke. Water applied to the body helps remove heat while veterinary care is arranged. Do not spend time searching for a particular water temperature before starting cooling with available water that is cooler than your dog.

If you have no water:

• Move your dog into the nearest cool or shaded place immediately.
• Ask someone to bring water or arrange collection.
• Contact a nearby business, home or clinic for help.
• Avoid making a struggling dog walk farther to reach a tap.
• If there are warning signs, call an emergency vet while arranging assistance.

For future outings, carry water for drinking and emergency cooling. If you cannot provide enough water or reliably refill, shorten or cancel the outing.

How long does heatstroke take to set in?

It can develop within minutes in dangerous conditions, but there is no predictable countdown. A dog in a hot, poorly ventilated vehicle can overheat extremely quickly. Exercise adds internally generated heat, so a running dog can become dangerously hot even when the air temperature seems fairly moderate.

Risk depends on the combination of temperature, humidity, sunlight, airflow, activity and the dog’s ability to cool themselves.

A short walk is not automatically safe. Neither is sitting still in a sunny garden. Do not use rules such as “we have only been outside for ten minutes” to dismiss concerning signs. Heat-related illness can occur without exercise.

When is it too hot to walk a double-coated dog?

There is no single air temperature that makes every double-coated dog safe or unsafe.

As a conservative planning guide, temperatures around 20°C (68°F) should prompt you to reassess the usual walk. At 25°C (77°F) or above, especially in direct sun or humid conditions, favour postponing routine exercise for a thick-coated dog and using brief essential toilet trips instead.

These are precautionary planning prompts, not validated safety boundaries. Some dogs struggle at lower temperatures. Guide Dogs’ hot-weather advice also recommends increasing caution above 20°C and taking greater care at 25°C.

Use the conditions and your individual dog to decide:

• Cool conditions, a shaded route, a comfortable dog and water available: choose a gentle walk suited to their fitness.
• Warm sunshine, humid air, little breeze or a dog that heats up easily: shorten substantially or postpone.
• Hot, humid conditions or heavy panting before you start: skip recreational exercise and use a cool indoor activity.
• Any warning signs during the outing: stop, cool and seek veterinary advice.

Choose the coolest actual conditions, rather than assuming sunset makes everything safe. Pavements and enclosed spaces can remain hot. A surface that feels too hot to your hand is unsuitable for paws, but a comfortable surface does not prove the air is safe for exercise.

Does a double coat protect my dog from heat?

A double coat has an undercoat and an outer layer of guard hairs. It provides insulation and skin protection, but it does not make a dog heatproof.

Coat type also varies. A Labrador’s short double coat and a Samoyed’s dense coat are not identical.

Brush regularly to remove loose hair and prevent matting. Do not automatically shave a double-coated dog as a heatstroke prevention measure. Discuss suitable grooming with your vet or groomer, particularly if the coat is matted or there is skin disease. Close clipping can reduce sun protection and alter coat regrowth.

Whatever their haircut, your dog still needs appropriate weather, shade, water and sensible activity.

Does humidity increase the risk of heatstroke?

Yes. Humidity makes panting less effective.

Dogs lose heat as moisture evaporates from their respiratory surfaces during panting. When the surrounding air is humid, evaporation becomes less effective, making it harder to release heat.

That means a warm, sticky day can be more demanding than the thermometer suggests. Heavy panting may show that your dog is working hard to cool down without succeeding.

Use humidity as a reason to reduce activity further. A cloudy sky or an evening walk does not remove the risk if the air remains warm and humid. Treat a weather app’s “feels like” temperature as another warning, rather than a dog-specific safety calculation.

Which dogs need extra caution?

Any dog can overheat, but take particular care with:

• Flat-faced dogs, especially those with noisy or restricted breathing.
• Thick-coated dogs and large or giant breeds.
• Overweight or poorly conditioned dogs.
• Puppies and elderly dogs.
• Dogs with heart or respiratory disease.
• Dogs not accustomed to the current climate.

Being fit, young or enthusiastic does not guarantee protection. Some dogs continue playing despite becoming dangerously hot, so owners need to set the limit.

Could the panting be caused by something else?

Yes. Pain, anxiety, fever, airway problems, heart or lung disease, and some hormonal conditions can also cause excessive panting.

Arrange an examination if panting is new, unusually heavy, happens at rest in a cool room or repeatedly seems excessive for the activity. Noisy breathing and reduced exercise tolerance deserve attention, even if they have gradually become familiar.

Breathing difficulty is urgent regardless of whether heat is the cause.

Does my dog still need a vet after cooling down?

Yes, if heatstroke was suspected or there were significant warning signs.

Looking brighter or having a lower temperature after cooling does not rule out internal injury. Heatstroke can cause kidney damage, clotting problems and shock.

Your vet may assess temperature, circulation, breathing and neurological function, then check blood and urine results. Treatment can include controlled cooling, intravenous fluids, oxygen and management of complications.

Recovery depends on the severity and duration of overheating, underlying health and how quickly treatment begins. Some dogs need hospital monitoring and repeat tests because complications can become apparent later.

Common mistakes to avoid

• Waiting for a time limit. A planned ten-minute walk can still be too much.
• Assuming a drink fixes overheating. Suspected heatstroke needs body cooling and veterinary care.
• Continuing because the dog wants to play. Enthusiasm does not measure heat tolerance.
• Wrapping the dog in wet towels. Apply water directly and allow airflow.
• Relying on a haircut or cooling accessory. Neither makes hot-weather exercise safe.
• Cancelling the vet visit after apparent improvement. Significant heat illness can have delayed consequences.

How to plan safer outings

Check temperature, humidity and the route before leaving. Choose short routes near shade, water and an easy way home. Take a phone, drinking bowl and sufficient water, and know where the nearest veterinary clinic is.

Avoid running, cycling alongside your dog and repeated ball chasing during warm conditions. On unsuitable days, use calm indoor scent games, food searches or short training sessions in a cool room.

Keep drinking water available at home and provide somewhere comfortably cool to rest. Never leave your dog unattended in a vehicle.

Make the plan work for everyone caring for your dog

Agree on a hot-weather alternative with family members, dog walkers and sitters before a heatwave. Give them the clinic’s number, show them where the water and bowl are kept, and make clear that a missed recreational walk can be replaced with a calm activity in a cool room.

For a scent game, hide a few pieces from your dog’s usual food allowance around one cool room. For training, practise familiar cues without running or repeated chasing. Keep the session low-key, then leave your dog somewhere comfortable to rest.

Plan the whole outing, including the trip home. A shaded destination does not help if the route there is exposed or the return journey means waiting beside a hot road. Choose routes with straightforward exit points and a reliable way to get help if needed.

Frequently Asked Questions

Can a dog get heatstroke just lying in the sun?

Yes. Exercise is not required. Move a heavily panting dog into a cooler environment rather than assuming they will move themselves before overheating.

Should I use cold water or wait for lukewarm water?

Ordinary cold tap water is appropriate for immediate cooling. Do not delay while trying to find lukewarm water. Apply it calmly to the body and keep it away from the airway.

Is a fan enough to cool an overheated dog?

A fan helps when combined with wetting the body. It should not be the only response to suspected heatstroke, and it does not replace veterinary treatment.

Can I restart the walk once my dog stops panting?

If your dog became overheated, end the outing and allow recovery somewhere cool. If there was heavy persistent panting, weakness or another warning sign, seek veterinary advice instead of testing their tolerance again.

Is walking at night always safe?

No. Air, ground and humidity can remain unsuitable after dark. Choose genuinely cooler conditions and adjust the plan to your dog.

The key decision

A hot-weather walk should never depend on guessing how long your dog can cope. Stop early, cool promptly and seek urgent veterinary help when warning signs appear. No fixed walking time, coat type or weather-app reading can override what your dog is showing you.

Sources and further reading

• Cornell University: recognising overheating and planning safer summer activity
• Royal Veterinary College: why prompt cooling matters
• RECOVER first-aid guidelines for dogs and cats: heat-related illness
• Veterinary research review: heat-illness risks, severity and cooling methods

For everyday planning and keeping useful health information together, the ASK A VET™ app can support your dog’s ongoing care. Suspected heatstroke needs immediate in-person veterinary care; do not wait for an online response.