COLUMBUS, Ohio (WCMH) – The dog days of summer are upon us in Columbus, and there are more of them than ever before.

That common saying is not just a casual expression, according to the National Weather Service. It can be traced back to the Roman Empire and refers to July 3 through Aug. 11. Those dates are 20 days before and 20 days after the star Sirius (the “dog star”) rises and falls with the sun.

The dog days of summer are normally the hottest and most humid days of the year, and research released last week shows Columbus – along with most of Ohio and the U.S. – is seeing more as temperatures rise due to human-caused climate change.

Researchers at the nonprofit Climate Central defined “dog days” as when the air temperature reaches 77 degrees Fahrenheit, which is when asphalt can heat to 125 degrees and burn unprotected skin and dog paws.

Using historical weather station data for cities across the nation, researchers found Columbus is seeing 26 more days of 77+ degrees than in 1970.

Columbus has experienced the largest increase of the 10 Ohio cities Climate Central studied. Nine of those cities have seen increases, with the lowest being 14 more 77-degree days in Dayton.

Of the 246 American cities researchers looked at, 232 (94%) have seen an increase in dog days in the past 50 years. Bluefield, Virginia, and Tucson, Arizona, saw the largest increases: 45 days and 40 days, respectively.

What more ‘dog days’ means for your dog

More uncomfortably hot days in the peak of summer mean owners should pay extra attention to their pets’ health along with their own.

“Across the board, animals can get overheated very quickly” said Dr. Missy Matusicky, an assistant professor at The Ohio State University College of Veterinary Medicine.

When outside temperatures reach the high 70s, asphalt in the direct sun can heat to well over 120 degrees, burning dog paws when out on a walk in the middle of the day.

“If you don’t feel comfortable stepping on your bare feet on that pavement and standing there for a second,” Matusicky said, “then don’t let your dog walk on it.”

Since pavement cooks at the height of summer days, Matusicky advises walking your dog in the early morning (like 7 a.m.) or the late evening (after 8 p.m.). And if you do find yourself out in the afternoon with your dog, keep it short and bring plenty of water.

The biggest risk to dogs on hot days is heatstroke, when body parts start to shut down to cope with temperatures. Heatstroke can include gastrointestinal distress, neurologic impairment, acute dehydration and even damage to the heart and kidneys.

“There’s this slow progression, this gray zone where sometimes they can recover on their own, sometimes they need to be seen by a vet,” Matusicky said, “(but) sometimes they need to be hospitalized when they’re very, very ill and may die from it.”

Unlike humans, pets cannot sweat to deal with high heat and humidity, so they pant. But like humans, some dogs are more susceptible to the heat than others. Think puppies, older dogs and dogs with underlying health conditions.

“I just saw a puppy the other day,” Matusicky said. “It had played for hours out in the 90-degree heat, and then that evening it was vomiting, it was having diarrhea, it was just kind of listless and not acting right.”

Breeds also make a difference. Short-muzzled dogs like bulldogs and Boston Terriers are less able to pant, and black-furred dogs “will get physically very hot to the touch,” Matusicky said.

“They will lay in the sun and you need to be there,” she said. “Some people say, ‘Oh, but they love it.’ Well, yeah, they might not know that. They might not know any better.”

Heatstroke among cats, however, is rare, Matusicky noted. Cats are more often indoors and thus in climate-controlled environments, but they also have better self-awareness in the heat than dogs. Matusicky said that a dog’s motivation to play can “supersede any actual physiologic health that they might think about.”

“Dogs will wrestle and play because it’s fun and they don’t realize they’re pushing it too much,” she said. “Cats are like ‘Hey, no, that’s not good for me. I’m going to quit.’”

And one rule with no exception in the summer for dogs: don’t leave them in the car.

“Never, ever, ever think that in the summertime leaving your dog in a car for any period of time is acceptable,” Matusicky said. “If it hits your brain and you think, ‘Huh, is that too long?’ Yes, it is. Always, yes. Do not do that.”