The signs of heatstroke in dogs and cats: What to look out for

Aotearoa summers are made for outdoor fun, walks on the beach, backyard barbecues, and plenty of sunshine. But for our pets, hot weather can also bring a serious health risk: heatstroke.

Heatstroke can come on quickly and be life-threatening if not treated straight away. With a little knowledge, you can learn how to spot the early signs of heat stress, protect your pet from overheating, and respond if the worst happens.

What is heatstroke in pets?

Heatstroke happens when your pet’s body temperature rises to dangerous levels and they cannot cool themselves down. Dogs and cats have a normal temperature range of about 38 to 39°C. If this climbs above 41°C, it can cause organ damage, brain injury, or even death.

Our expert, Dr Rosalind Holland (BVSc, MVM, MANZCVS) explains that heatstroke differs from a fever in that a fever is an internal response to fighting an infection, while heatstroke is a response to environmental conditions.

Signs your pet may be overheating

“Heatstroke is a very serious and often fatal illness that is an emergency,” Dr. Holland goes on to say. “Prevention of heatstroke is important as treatment can be challenging.”

To prevent heatstroke and a potentially life-threatening situation, it’s best to get familiar with the classic signs and symptoms of heatstroke in dogs so you can act quickly. Here’s what to look for:

• Excessive panting or drooling - dogs and cats cannot sweat to release excess heat from the body; instead, they pant
• Rapid or laboured breathing
• Weakness, wobbliness, or collapse
• Bright red or blue-tinged gums and tongue
• Seizures in severe cases
• Behavioural response: seeking shade, avoiding exercise or activity, and drinking an excess amount of water

Pets most at risk of heatstroke

“By far the biggest risk for heatstroke is the inability to pant effectively to reduce heat load,” Dr. Holland explains.

“Brachycephalic animals – those with short noses, such as Pugs, Pekingese, French bulldogs, and Persian cats are more at risk than animals with a more normal anatomy.”

Additionally, other factors can lead to an increased risk of heatstroke as these pets cannot regulate their body temperature as effectively, that means they need extra care and supervision on warm days.

• Pets with thick or dark coats
• Overweight animals
• Older pets
• Pets with existing breathing, heart, or lung conditions

How to prevent heatstroke in hot weather

As Dr. Holland has stressed already, prevention is always better than a cure (which is true for many things!). Luckily, there are plenty of ways to offer relief from the heat:

• Never leave pets in cars, it can prove fatal. Even on cooler days, the temperature inside a vehicle can skyrocket in minutes, becoming much hotter than the ambient temperature outdoors. It is illegal in New Zealand to leave a dog in a car if they are showing signs of heat stress. Fines start at $300.
• Avoid midday walks in the peak of summer. Stick to early morning or evening when the ground and air are cooler.
• Don’t push your pet to exercise if they are showing they are tired and hot.
• Always provide shade and water. Offer multiple bowls of fresh water and safe cool spots indoors and out.
• Use frozen treats. Fill chew toys with kai and freeze overnight for a refreshing challenge.
• Fill up a paddling pool or set up the sprinkler for some refreshing fun for your dog.
• Check sheds and garages. Cats can sneak inside and become trapped in dangerously hot spaces.

What to do if your pet has a heatstroke

When your pet is under stress, it’s easy to lose your cool. If you suspect heatstroke, stay calm, act quickly and follow these steps:

• Call your vet immediately. Describe their symptoms and follow their instructions.
• Move your pet to a cool, shady place.
• Begin active cooling (cool first, transport second):
  • Offer small amounts of cool (not icy) water.
  • Wet their coat with cool water or cool, damp towels.
  • Use a fan to create airflow.
  • Place them on a damp towel or cooling mat, but do not cover them.
• Transport them safely to the vet – keep windows down or air conditioning on during the drive.

Dr. Holland issued a warning on cooling your pet quickly: “Don’t use ice or chilled water on skin, as this can cause constriction of skin blood vessels and heat retention.” 

When trying to cool your furry friend down, avoid putting them in a cold bath or giving them a cold shower. Sudden temperature changes can actually make things worse by causing their body to retain heat instead of releasing it. Instead, gently cool them with room-temperature water, offer small sips of cool (not icy) water to drink, and move them to a shaded or air-conditioned area.

New research: why water is key to cooling dogs

Recent research from Scotland’s Rural College has confirmed what many vets have long recommended: using water for active cooling is the most effective way to treat overheating in dogs.

The study compared different cooling methods and found that wetting the coat with room temperature water was more effective than shade or fans alone. This reinforces SPCA’s advice that water is your best tool if your dog shows signs of overheating.

Dr. Holland agrees: “If they are conscious and can lap and swallow normally, offer small, frequent amounts of water for them to drink.”

Can your pets get sunburnt?

Sunscreen is important for pets, just as it is for humans. Your furry mates should avoid the sun's harsh rays or have pet-safe sunscreen applied before heading out. Pay extra attention to areas with less fur or lighter skin, such as their nose, ears, and belly — as these spots are more prone to sunburn.

Normal sunscreen ingredients include zinc oxide, which can be toxic to animals, so pet-friendly sunscreen is best for dogs and cats.

And finally, be mindful of hot weather alerts. Remember the five second rule, if it's too hot for you, it's probably too hot for them as well.

Keeping your four-legged friends safe

Heatstroke can be frightening, but with awareness and quick action, you can protect your pets. Keep them cool, know the warning signs, and never hesitate to call your vet if you are worried.

And for extra peace of mind, SPCA Pet Insurance may be worth considering should sudden vet visits pop up. It may help protect your wallet against the burn out of unexpected bills.