Lab swimming in a pool

Many dogs love summer as much as we do, but high temperatures can present a problem for our canine friends.

We talked with Dr. Debbie Mandell, staff veterinarian and adjunct associate professor at the University of Pennsylvania’s Matthew J. Ryan Veterinary Hospital, about what factors can increase your dog’s risk of heat-related injuries and even death. Heatstroke is one of the many problems that veterinarians at Ryan see in the 13,000 emergency cases that come through their doors each year. Here are five factors that Dr. Mandell says can put your dog at risk for heat stress.

What Makes Some Dogs More Vulnerable

1. Congenital defects or underlying respiratory problems. One of the top risk factors, Dr. Mandell says, is upper-airway problems. You may coo at every adorable, flat-faced dog on your block, but breeds like Pugs, Bulldogs, French Bulldogs and Boxers can suffer from brachycephalic airway syndrome. Unlike humans, who sweat when we’re hot, dogs use their respiratory system to get rid of heat — and these flat-faced breeds’ airway abnormalities put them in danger of heatstroke when they’re exposed to higher temperatures.

Another underlying respiratory condition that can land dogs in big trouble is laryngeal paralysis, which is common in medium and large breeds like setters, Labradors and Pit Bulls. Additionally, small dogs like Yorkshire Terriers, Pomeranians and Maltese are commonly affected by collapsing tracheas. In both of those situations, Dr. Mandell explains, the dogs will pant to release heat, and their panting causes swelling in the airway, which causes them to pant harder, which results in more swelling. “They enter this vicious cycle where they get worse and worse really quickly,” Dr. Mandell says.

2. Not being acclimated to hot weather. “On the first hot day, everyone wants to go for a run with their dog or play outside in the yard,” Dr. Mandell says. “Dogs are not going to stop, even when they can’t breathe or are about to collapse.”

It’s up to you, then, to know the signs of heat stress, so you can help your dog cool down before it becomes an emergency. Those signs include excessive panting and drooling, a fast pulse and gums that have changed in color from pink to bright red. Vomiting and bloody diarrhea are signals that the heat may have started to affect internal organs.

3. Being kept outdoors without access to shade and water. It can be dangerous for an indoor dog to overexert himself in hot weather, but pets who are primarily housed outdoors are also in danger. “As much as we try to discourage it,” Dr. Mandell says, “there are people who have outdoor dogs.” Keeping a dog outside in the summer, especially without appropriate access to shade and cool water, is a risk that’s not worth taking.

4. Being left in the car. Speaking of risks that aren’t worth taking, it is never OK to leave a pet in a hot car. “It’s been documented that the temperature inside a car can reach over 120 degrees in minutes,” Dr. Mandell says. “If you have that window cracked a tiny amount, it’s really not going to help.” Fortunately, Dr. Mandell says, thanks to lots of recent news stories about dogs (and even children) being left in cars, she’s not seeing as many of those cases.

If you see an animal locked inside a hot car, there are steps you can take to help rescue it safely. The Humane Society of the United States, and the ASPCA recommend that you write down the car’s make, model and license plate; attempt to locate the owner; and call animal control or your local police department for help.

5. Obesity. While it is not a congenital defect like brachycephalic airway syndrome, obesity can certainly put your pet in harm’s way when it comes to heat stress. It makes dogs more susceptible to many issues — like joint and back problems — and heatstroke is no exception.

Dr. Mandell explains it this way: While some heat can escape through the respiratory system through panting, “70 percent of the heat loss in dogs and cats occurs by radiation and convection through the skin.” When the core body temperature rises, blood vessels dilate, the heart pumps harder, and there is increased blood flow to the skin, where heat is lost to the environment. In obese dogs, the large layer of fat under the skin serves as insulation and can prevent some of that heat from getting to the skin to be released.

One last note: An extremely thick coat of fur can cause the same situation, so you should also watch closely for signs of heatstroke if you own a furry breed like the Newfoundland or Great Pyrenees.

And if you think your dog is experiencing any of the signs of heatstroke, contact your veterinarian or local emergency clinic immediately.

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