Heatstroke in dogs and cats: what every pet owner should know

Warm weather can be lovely for both pets and people - but it can also become dangerous surprisingly quickly. Every summer, veterinary teams see dogs and cats struggling with overheating, and in some cases, this can develop into heatstroke, a serious medical emergency.

The important thing to know is that heatstroke is often preventable. Recognising the early warning signs, knowing which pets are more vulnerable, and acting quickly if your pet becomes too hot can make a real difference.

What is heatstroke?

Heatstroke happens when a pet’s body temperature rises beyond what they can safely control on their own. Once this happens, the body can no longer cool itself effectively, and overheating begins to affect vital organs such as the brain, heart, lungs, kidneys and gut.

This is why heatstroke is not simply a case of “being too warm”. It is a potentially life-threatening condition that needs urgent attention.

Why pets overheat more easily than we think

Dogs and cats cope with heat very differently from humans. They do not sweat through their skin in the same way we do, so they have fewer ways to get rid of excess body heat.

Dogs rely heavily on panting to cool themselves down, while cats tend to seek cool places, rest more and groom to help regulate their temperature. But if the weather is very warm, the air is humid, or a pet is unable to cool off properly, body temperature can rise quickly.

In some cases, this happens because of the environment - for example being trapped in a hot car, a conservatory or a poorly ventilated room. In other cases, it happens because a pet has been walked, exercised or become overexcited in warm weather and simply cannot lose heat fast enough.

Can cats get heatstroke too?

Yes - although we tend to hear more about heatstroke in dogs, cats can absolutely overheat as well.

In fact, heatstroke in cats can be easy to miss at first because the signs may be more subtle. Cats are often good at hiding discomfort, so by the time they appear obviously distressed, they may already be quite unwell.

Common causes of heatstroke

A lot of owners associate heatstroke with pets being left in cars - and that is certainly one of the most dangerous situations - but it is far from the only one.

Heatstroke can develop when a pet:

• is left in a parked car, even for a short period

• is walked or exercised during the hottest part of the day

• becomes overexcited or overactive in warm weather

• is kept in a hot conservatory, room or enclosed outdoor area

• lies in direct sun without access to shade

• travels in a warm car with poor ventilation

• already has breathing difficulties or other health issues that make cooling harder
  

Which pets are most at risk?

Any dog or cat can overheat, but some pets are much more vulnerable than others.

Pets at increased risk include:

• flat-faced breeds such as Pugs, Bulldogs, French Bulldogs, Persian cats and Exotic Shorthairs

• older pets

• very young animals

• overweight pets

• pets with heart, airway or lung disease

• pets with thick or heavy coats

• anxious, excitable or highly active pets

Flat-faced pets deserve a special mention because they already have to work harder to breathe normally. Since panting is such an important way of cooling down, anything that affects airflow can increase the risk of overheating.

Signs of heatstroke in dogs and cats

The signs of heatstroke do not always appear all at once. Often, the first changes are relatively subtle - but they can worsen quickly.

Early signs to watch for

• heavy or unusually fast panting

• restlessness or agitation

• drooling more than normal

• bright red gums or tongue

• seeming unusually tired after mild activity

• searching for cool places and being unable to settle

• faster breathing or a racing heart
  

More serious signs

• weakness or wobbliness

• vomiting or diarrhoea

• confusion or disorientation

• collapse

• pale gums

• tremors or seizures

• loss of consciousness
  

A special note for cat owners

If a cat is breathing with its mouth open, seems distressed in warm weather, is drooling, very lethargic, vomiting, or unable to settle, this should be treated as urgent.

What should you do if you think your pet is overheating?

If you are worried that your dog or cat may be suffering from heatstroke, do not wait to see if they improve on their own.

Heatstroke is an emergency, and the best approach is to start cooling your pet immediately while contacting a vet for urgent advice.

First aid: what to do straight away

1. Move your pet somewhere cool

Take them out of direct sunlight and into a cooler, shaded or well-ventilated area as quickly as possible. Stop any exercise or activity straight away.

2. Begin cooling them down

Use cool water over the body - for example by pouring water over them, wetting the coat thoroughly, or using cool wet cloths while ensuring there is airflow around them. A fan can also help if one is available.

The aim is to bring body temperature down safely and steadily while you arrange veterinary care.

3. Offer small amounts of water if they are awake and able to drink

If your pet is conscious and able to swallow normally, you can offer small amounts of cool water. Do not force water into their mouth.

4. Call your vet without delay

Even if your pet seems to improve after cooling, they should still be assessed. Heatstroke can affect the body in ways that are not always obvious from the outside, and some complications may only become apparent later.

What not to do

When a pet is overheating, well-meant first aid can sometimes make things worse. Try to avoid the following:

• do not leave them to “recover and see how they go”

• do not force them to drink

• do not wrap them tightly in wet towels, as this can trap heat rather than release it

• do not delay contacting a vet if signs are severe

• do not assume it is only heatstroke if the weather is extremely hot - pets can overheat in surprisingly mild conditions depending on activity, humidity and individual risk factors
  

Why veterinary assessment is still important

One of the reasons heatstroke is taken so seriously is that the effects do not stop at the skin surface. When body temperature becomes dangerously high, it can place strain on the entire body.

Heatstroke can affect:

• breathing and circulation

• the gut and liver

• kidney function

• blood clotting

• the nervous system

That means a pet may look brighter after initial cooling but still need treatment, monitoring or blood tests to make sure there has been no internal damage.

How is heatstroke treated at the clinic?

Treatment depends on how unwell the pet is and how quickly they are seen, but may include:

• continued active cooling if needed

• intravenous fluids

• oxygen support

• monitoring of temperature, heart rate and breathing

• blood tests to check organ function and hydration

• medication for vomiting, gut upset or other complications

• hospitalisation for observation in more serious cases

The sooner a pet receives treatment, the better the chances of a smooth recovery.

Preventing heatstroke: simple steps that matter

Prevention is always better than emergency treatment, and a few small changes can greatly reduce the risk.

In warm weather:

• never leave your pet in a parked car

• make sure fresh drinking water is always available

• provide shade and access to a cool resting place

• avoid walks during the hottest part of the day

• keep exercise gentle in hot or humid weather

• be especially cautious with flat-faced, elderly or overweight pets

• keep indoor spaces well ventilated

• remember that conservatories, enclosed gardens and sunny rooms can become very hot very quickly

For dogs

In hot weather, early morning and late evening are usually the safest times for walks. Some dogs - particularly brachycephalic breeds, older dogs and dogs with breathing issues - may need much shorter walks or even a rest day during very warm spells.

For cats

Make sure indoor cats can move away from sunny windows and hot rooms, and always have access to fresh water and cooler areas of the house. Outdoor cats should also have access to shade.

Final thoughts

Heatstroke is one of those emergencies that can escalate quickly, but it is also one of the most preventable.

If there is one message we would want every owner to remember, it is this: if your pet seems too hot, distressed, weak, or unusually breathless in warm weather, act early. Move them somewhere cool, begin gentle cooling, and contact your vet straight away.

If you are ever unsure whether your pet may be overheating, our team is always happy to advise.