Photo: Dr. Rebecca Jackson with her dog Whisky. The Calgary-based veterinarian says she keeps their walks to the early morning and late evening on very hot summer days to reduce the risk of heat-related health issues. (Leanne Moreira)

By Eva Lam - CBC News - July 24, 2022

Veterinarian Dr. Rebecca Jackson was working in an Alberta mountain town a few summers ago when a patient came in showing signs of heatstroke.

The dog had just had a long day of hiking and was disoriented, vomiting, panting heavily, and "very, very weak," she recalled. "He had a high elevated heart rate, he had low blood pressure. His body temperature was elevated."

He was immediately put on intravenous fluids and wrapped in cool towels. Isopropyl alcohol was applied to his paw pads for an evaporative cooling effect. He was also given an anti-nausea injection to prevent any further dehydration through vomiting.

The story has a happy ending: The dog's body temperature came down and he made a full recovery, Jackson said. 

But it's a reminder during these hazy, humid days of summer that humans aren't the only ones feeling the heat — pets are, too. And with even hotter days projected to come, veterinarians say it's important to take precautions and watch for signs of trouble in your furry family members.

Mind their paws

Heatstroke may be top of mind for pet owners since it's something that humans can also suffer from. But burnt paws are actually a more common summertime injury — and one that can be easy to overlook, said Jackson, an instructor at the University of Calgary's faculty of veterinary medicine.

Imagine walking barefoot across a sidewalk or beach on a hot summer day, and you get some idea of what our four-legged friends go through.

"We forget that they're very unique in that their paw pads are touching the ground as they walk," she said. "Black pavement in particular can attract a lot of heat and can cause burn injuries to those paw pads."

Severe burns on paw pads can be tough to heal because the surface of the pads is relatively avascular, meaning that it's lacking in blood supply. On very hot days, consider keeping your pet inside and walking them only in the early morning or late evening when temperatures are cooler, Jackson said.

If you're unsure, the American Kennel Club suggests placing the back of your hand on the asphalt on hot days; if you can't comfortably hold it there for 10 seconds, it's too hot for your pup's paws. 

Why pets can overheat

If you do take your pet out on a hot day, watch for signs of heatstroke, which happens when the body is unable to cope with external heat.

As humans, we regulate our body temperature in part through sweating: the evaporation of sweat from our skin's surface removes excess heat and cools us down. But our pets don't have sweat glands distributed throughout their body in the same way.

In dogs and cats, the sweat glands are mostly located in the paw pads. It's such a small surface area that it doesn't help much with temperature regulation, according to Dr. Sarah Machell, a licensed veterinarian and medical director of Vetster, a telehealth app that connects pet owners to veterinarians for virtual consults.

That's why our pets pant in the heat — it's their way of cooling off.

"[Panting is] the only way that pets — dogs, in particular, we see this in — can really evaporate water from any surface to help lower body temperature," Machell said.

"So their capacity and their tolerance for heat is much, much less than humans."

To help your pets stay cool, make sure they have lots of access to shade and that any exercise taken on is very moderate and at a slow pace, Machell said. Keep them hydrated by carrying water bottles, taking frequent breaks and encouraging them to drink.

Specialized cooling bandanas and cooling vests can also keep your pets from getting overheated, Machell said.

Most pet owners know to never leave their pets alone in a car because of how fast temperatures can rise in the enclosed space. Machell recommends planning ahead and taking a second person with you who can walk the dog while you pop into the store.   

Signs of heatstroke

As with humans, it only takes a few degrees of difference in your pet's body temperature for the situation to tip into dangerous territory.

A normal body temperature for a dog is in the range of 37.5 C to 39.2 C. When it gets above 41 C, the possibility of heatstroke starts to be a significant concern, and there is risk of multiple organ failure and death, said Dr. Matthew Richardson, a veterinarian at The Animal Clinic in Toronto and president-elect for the Ontario Veterinary Medical Association (OVMA).

The higher above that level it goes and the longer it is elevated, the more serious the consequences, he said.

According to the OVMA, the signs of heatstroke in pets can include:

• Excessive panting.
• Muscle twitching.
• Anxious or dazed look.
• Vomiting.
• Weakness.
• Increased drooling.
• Diarrhea.

While symptoms are fairly similar across pet species, there are some minor differences.

"In dogs, we will see vomiting and diarrhea as symptoms of heatstroke. In birds and reptiles, it tends to be a reduction in the production of fecal matter and a reduction in the amount that they want to eat," Richardson said.

If you think your pet is suffering from heatstroke, you should move them to a cooler setting and use cool — not cold — water and damp towels to try to lower their body temperature, according to the OVMA. If they are able, allow them to drink. Bring any pets suffering from heatstroke to a veterinarian as soon as possible, the OVMA says.

Pet owners should also be aware that some animals are more vulnerable to heatstroke than others. The Toronto Humane Society says these include animals with flat faces, such as pugs and Persian cats, as they can't pant as effectively; elderly pets; overweight pets; and those with heart or lung diseases.

A puppy would also be more prone to heatstroke than an adult dog, Richardson said.

Keeping cool indoors

Heat stress can also be an issue for indoor pets if there is a lack of air conditioning.

Machell suggests having multiple locations for access to fresh water and adding ice cubes to water or even using a water fountain, since running water can sometimes be more appealing for pets.

For pets like birds and guinea pigs, make sure the cage is out of direct sunlight, and you could place a fan on them, Richardson said.

For small mammals, you can also try to create a special spot for them in their cage that will retain a cooler temperature for longer than regular bedding.

"If you can find a piece of stone, tile, granite, something like that that's cool — and can stay in the shade so it stays cool — you can put that in their cages," he said. "You can have this sort of cold area where they can go to try to find that cooler spot."