Dogs of all breeds should be protected from extreme heat.

Ranger is a young, active, healthy retriever. But he was out of sorts after spending a bright day playing fetch with his Frisbee-throwing owners. They noticed he was panting heavily and uncontrollably, and his saliva was thicker than usual.

Ranger’s next outing was to the veterinarian, where he was diagnosed with heat stress. He needed intravenous fluids and was hospitalized overnight.

He recovered, and his owners learned an important lesson: The sweltering “dog days” of summer can harm household pets.

Both dogs and cats face the same summertime risks, veterinarians say. But dogs are more vulnerable than cats because they usually spend more time engaging in outdoor activities with their owners.

Heat-related injuries like Ranger’s are probably the biggest summertime concern, said Dr. Kristina McElroy, a veterinary public health officer and the Defense Health Agency’s Defense Support of Civil Authorities coordinator for veterinary services. She works with other federal agencies on disaster planning, preparedness, and response involving animal health, agriculture, and food protection.

McElroy said daily walks help dogs acclimate as temperatures rise. But on a hot day, “even just 30 minutes of strenuous activity at a dog park could stress some pets.”

“A general rule is, if it’s too hot for you then it’s even hotter for your dog,” said Army Col. Jennifer Chapman, a veterinarian and chief of plans and operations in the DHA’s Veterinary Service Branch.

Chapman and McElroy recommend limiting the amount of time pets spend in the sun during hot and humid stretches. When they do venture out, make sure there’s a shady spot where they can rest, and ensure there’s plenty of cool, clean water for them to drink.

Also, keep in mind that hot sidewalks and streets can burn paws. Walk dogs in the cooler morning and evening hours, McElroy said, and if that’s not possible, “try paw protectors, or walking in the grass instead.”

Dogs with light skin or fur also can get sunburned. Chapman advises sunblock made specifically for animals because sunblock for people may contain zinc oxide and other ingredients that are toxic to pets. Pay attention to sparsely haired areas such as the nose, tips of ears, and the belly for pets that enjoy stretching out in the sun on their backs.

Heat can be deadly when pets are trapped in vehicles. Chapman notes that even in mild weather, temperatures inside cars can rise dangerously high in a matter of minutes. For example, on a comfortable 80-degree day, the inside of a vehicle can reach 100 degrees in about 10 minutes.

“It’s not enough to crack the windows, even if you’re going to be gone for only a few minutes,” Chapman said. “Never, ever leave a pet inside a car.”

Other outdoor hazards for pets include stinging and crawling insects such as wasps, mosquitoes, and fleas; and arachnids such as ticks and spiders. Just like people, pets can have an allergic reaction to stinging insects, McElroy said. Signs include swelling in the face and difficulty breathing. If you notice any of these, take your pet to the veterinarian as soon as possible.

Mosquitoes and ticks carry diseases that are harmful to pets as well as to humans.

“Let’s say you take your dog for a walk in the woods,” McElroy said. “If your pet isn’t protected, a tick can crawl onto it and use it as a bus, of sorts, until it can get to you. So year-round protection for pets helps their owners as well.”

For more information on hot weather pet safety, download a copy of a brochure published by the Army Public Health Center.