Your Guide to Heatstroke in Pets: What the Data Says

The scary thing about heatstroke is that heat problems do not always begin with a dramatic collapse. Sometimes they begin after a pet misses a drink. They can happen after a hot car journey or time spent in a sunny conservatory. A midday walk that seemed fine can be enough. Even a cat accidentally shut in a shed can end up in danger.

Key takeaways

• Heatstroke can affect dogs and cats, although dogs are often more at risk during walks, travel and outdoor activity.

• Heavy panting, drooling, weakness, vomiting, confusion, collapse or seizures need urgent vet advice.

• Cats can suffer heatstroke too, especially if trapped in hot spaces like sheds, garages, greenhouses or cars.

• Waggel data from 2024 to 2025 showed a sharp rise in heatstroke and dehydration cases.

• A skipped walk is better than a risky one. Your dog will forgive you, even after a dramatic sigh.

We looked at Waggel cases from 2024 to 2025 for both heatstroke and dehydration. Dehydration is useful to look at alongside heatstroke because it can act as a broader sign of heat stress. It may include less severe cases that still need veterinary care.

The timing matters. The Met Office reported that 2025 was the UK’s warmest and sunniest year on record, with multiple warm spells and heatwaves. You can read the Met Office update here: 2025 is a double-record breaker: UK’s warmest and sunniest year on record.

That does not prove that the weather caused every case. Pets can overheat for many reasons. But it does show why UK pet owners need to treat summer planning as normal care, not something reserved for extreme heat warnings.

You may not see every sign at once. Some pets show early warning signs first, then get worse quickly.

Signs of heatstroke in dogs:

• Heavy panting that does not settle

• Drooling or thick saliva

• Weakness, wobbliness or collapse

• Red, pale or unusual-looking gums

• Vomiting or diarrhoea

• Confusion, restlessness or distress

• Fast breathing or difficulty breathing

• Seizures or loss of consciousness

Our resident veterinarian, Aimee Warner, MCVs, says: “If your pet is excessively panting and they aren’t settling quickly with cooling efforts, seek veterinary attention. Don’t wait for them to get worse; the worse they get, the bigger the risks. No vet is ever upset/annoyed that an owner seeks veterinary attention too early!"

Dogs can overheat during walks, play, car travel, garden time or being left in warm rooms. Heatstroke is not only a “dog in a hot car” issue, although hot cars are still extremely dangerous.

Signs of heatstroke in cats

Cats are often quieter about discomfort, which makes heatstroke harder to spot. A cat may hide or become weak. They may start to breathe with an open mouth, drool, seem restless, vomit or collapse.

Cats can be at risk if they are trapped somewhere hot, such as a greenhouse, shed, garage, conservatory or car.

Older cats and kittens, as well as overweight cats and cats with breathing or heart conditions, may need extra care.

If your cat is open-mouth breathing, weak, collapsed, or acting strangely in hot weather, treat it as an emergency.

From our in-house vet, Aimee Warner:

"It’s hard to give one-size-fits-all steps, but the priority is always the same: cool first, transport second. Every minute counts, so you need to act immediately to lower your dog's temperature before you start your journey to the vet."

1. Seek shade and relief

• Your immediate goal is to halt any further rise in your dog's body temperature.

• Stop all movement: Cease exercise or play instantly.

• Seek shade: Move your dog out of the sun and into the coolest, most ventilated environment available, ideally somewhere with shade, a breeze, or air conditioning.

• Remove from danger: Get them out of any hot vehicles, conservatories, or warm buildings immediately.

2. Cool them down

• You need to help your dog release heat, but do so safely.

• Use cool water: Pour cool (not freezing or ice-cold) water over your dog. Focus on areas where the skin is thinner and blood vessels are close to the surface: the neck, stomach, and thighs.

• Avoid the head: Be careful not to pour water directly over their nose or mouth, as this can make breathing more difficult for a struggling pet.

• Create airflow: A fan, air conditioning, or a breeze from an open window is essential. Moving air helps evaporation, which is the most effective way to cool them down.

• Water submersion: If you have access to a stream or paddling pool with cool water, you can submerge them, provided they are alert and mobile. If they are elderly, have health conditions, or are unconscious, stick to spraying or pouring water to be safe.

3. See a vet

• Once you have started the cooling process, get to a vet promptly.

• Travel smart: Ensure your vehicle is as cool as possible (use air-con or open windows) for the journey to continue the cooling effect.

• Call ahead: Alert your vet that you are on your way with a suspected heatstroke case. This gives them time to prepare for your arrival, which can be critical.
  
  Aimee’s advice: "Avoid using ice baths, as these can cause blood vessels to constrict and actually trap heat inside the body. Also, don't force water into their mouth if they are struggling. Stay focused, keep them cool, and get them professional help as quickly as you can."

Pets do not cool down like we do. Dogs mainly rely on panting and only sweat a small amount through their paws. Cats tend to avoid heat where they can, but that does not help if they are trapped or unwell.

A dog can look fine at the start of a walk and be struggling 20 minutes later. A cat can seem “just sleepy” before you realise the spare room has turned into a tiny sauna in the midday sun.

There are a few common risk moments:

Any pet can get heatstroke. Some may need extra care, including:

• Flat-faced dogs and cats

• Older pets

• Puppies and kittens

• Overweight pets

• Pets with heart or breathing conditions

• Thick-coated dogs

• Very active dogs who do not know when to stop

• Pets recovering from illness or surgery

Flat-faced breeds, such as Bulldogs, Pugs, French Bulldogs and Persian cats, may be more vulnerable because of their airway shape. This does not mean every flat-faced pet will suffer heatstroke. It means owners should be more cautious with heat, exercise and travel.

Our data points to a simple message. Heat stress is not rare enough to ignore.

If heatstroke cases rose from 11 to 30 and dehydration cases rose from 5 to 27 in the data reviewed, it suggests more pets needed help during hotter conditions. For owners, that means prevention matters long before an emergency.

Think about your pet’s day like this:

Hot weather changes the rules.

Your dog may not need their usual lunchtime walk. Your cat may need access to cooler rooms. Your puppy may need shorter play. Your older dog may need more rest. Your flat-faced pet may need the fan before anyone else in the house.

And yes, that may mean cancelling the walk. Dogs are allowed to be disappointed. They are going to be OK, despite their protests.

As with most things in life, prevention is usually easier than treatment. Small changes can make a big difference.

Keep fresh water available in more than one place. Walk dogs during cooler parts of the day. Avoid hard exercise in warm weather. Keep pets out of hot cars, conservatories and sunny rooms. 

Provide shaded areas in the garden. Use fans, cooling mats or damp towels where your pet tolerates them. Check on cats before closing sheds, greenhouses or garages.

For dogs, test surfaces before walks. If the pavement feels too hot for your hand, it is likely too hot for paws. 

For cats, look for hiding spots that may become heat traps. A cat choosing a sunny patch is normal. A cat trapped in a hot room is not.

If your pet has had heat-related illness before, speak to your vet about a safe summer plan.

If your pet seems too hot, weak, confused or unwell, move them somewhere cool and call your vet straight away.

On warm days, plan ahead. Walk earlier or later. Keep water nearby. Check sunny rooms. Never leave pets in cars, and give older, flat-faced or unwell pets extra breathing room.

And if your gut says, “This walk might be a bit much,” trust it. Missing one walk is not a big deal, but heatstroke is an emergency.