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Before leaving for work on a summer morning, Meredith turned on the air conditioner to keep her two beloved pets comfortable. Unfortunately, hours later, the power failed. Jazz and Ginger, gated in a sunny room, panted anxiously as they began to overheat. The house warmed quickly, and there was nowhere to find relief. Could this happen to your dogs?

Why Dogs Overheat

“Dogs don’t sweat,” former French Bulldog Club of America president Jan Grebe, Ph.D., reminds us.

Exercise, excitement, or infection can cause a dog’s temperature to rise normally. But when it rises only a few degrees over 102 degrees Fahrenheit, a dog is overheated and action must be taken before heat exhaustion occurs. When humans sweat, heat is transferred from the moisture over our entire body to drier, cooler air around it. Evaporation of this sweat cools us, and a fan makes it happen faster.

In contrast, dogs pant because they have few sweat glands. Panting is evaporative cooling, canine-style. Cooler, drier air is inhaled through the nose and upper airways, and in the lungs, it is exchanged for warm, moist air as evaporative cooling takes place, which is the dog’s equivalent of our sweating mechanism. The breathing rate increases from 40 to 400 breaths per minute, with an occasional deep breath. After the cooler air is sucked into the lungs, hot, moist air is exhaled through the mouth over the dripping tongue, expelling excess body heat.

Panting animals, then, need adequate cool water to drink on warm days to keep those airways moist for this process, maintaining a fragile temperature balance. But if the outside environment is also very moist, less evaporation and cooling occur, resulting in a reduced tolerance for hot, humid weather and a greater danger of overheating.

Flat-Coated Retriever laying down outdoors.

Signs Your Dog is Overheating

As a dog’s temperature rises, blood rushes to the surfaces of the tongue, gums, and membranes to help transfer excess heat. Frantic panting, extreme salivation, bright-red membranes, and labored breathing are clear warning signs that your dog is overheated and may quickly progress to a metabolic meltdown as his temperature rises to over 106 degrees Fahrenheit and he can no longer cool themself.

He may gasp for air, and the entire mouth will become grayish to purple because of the unmet oxygen demand. As he dehydrates, the saliva thickens, and he may vomit and have diarrhea. Unable to stand, he may have a seizure, become comatose, and die. Even if you can cool him and he acts normal, rush him to an emergency clinic because his organs may have already been damaged and death could follow.

Why Flat-Faced Dogs Overheat Easily

Brachycephalic dogs—with shorter, pushed-in muzzles, shortened facial bones, and noses that are pushed in and upward—tend to be more heat-sensitive, and their airways can be less efficient at moving air in and out of the lungs and thus more susceptible to overheating.

Grebe warns, “Anything that causes brachycephalic dogs to breathe harder places additional stress on their airways, whether it is overheating on a hot day, excitement that causes panting, or exercise that increases the oxygen demand of their muscles, requiring more strenuous breathing.”

Additionally, chronic respiratory challenges tend to cause irritation with more salivation and swelling in the throat, further impairing air movement as passages narrow. Eventually, the elasticity of the respiratory system is lost with repeated challenges, and with an increased effort to breathe, the walls of the airway may be drawn inward. Grebe explains, “Try pinching your nose shut, close your mouth, and inhale. Feel the walls of your larynx and trachea being sucked in.”

Over time, the increased effort to breathe causes a progressive inward collapse of the walls of the larynx, which may be fatal.

“Careful breeding of brachycephalic dogs should make good airways a priority in breeding stock,” Grebe says. Carrie Forsyth, who breeds and shows Pekingese, avoids the problem of overheating by selecting against pinched nostrils and other upper-respiratory abnormalities in her breeding program.

Pekingese standing in the grass.

How to Keep Your Dog From Overheating

  • Ensure that your dog has fresh water and shade, with short periods outside in hot weather.
  • Use a variety of cooling products
  • Don’t leave your dog in the car—with windows cracked or not. Even on a cool day (the mid-60s), the temperature in a closed car rises to 130 degrees Fahrenheit in minutes. The dog’s own body temperature increases the heat and moisture (especially for larger breeds), the oxygen is used up, and death can occur within 15 minutes.
  • Acclimate your dog to hot weather gradually and don’t exercise him on hot, humid days. Conditioned sporting dogs, even water retrievers, can overheat if the water is warm.
  • Make sure your home is cooled on warm days. Install a temperature alarm in your motor home, van, and house that dials your cell phone automatically. Dogs have been lost when air conditioners or power failed unbeknown to the owners.
  • Don’t place a crated dog where there is inadequate ventilation in warm, stagnant air under tents or in poorly ventilated buildings.
  • Carefully observe elderly dogs, those that are chronically ill, or pets with respiratory inefficiency.
  • Be vigilant with hairdryers anytime, especially cage dryers.
  • Although a dog’s coat can provide insulation, double coats make a dog more vulnerable to overheating and dark coats absorb heat faster in the sun.
  • Contact your veterinarian and your breed club and ask about heat sensitivity in your breed

Be Prepared

For preventive measures, she takes cool packs, towels, ice, and spray bottles wherever she goes with her Pekes in any weather. “You never know when it can become too warm,” Carrie warns. She lobbies for show superintendents to hold classes for brachycephalics in the morning and advises people to bring helpers when showing multiple dogs to watch over them.

If traveling alone, she advises people to carry two sets of car keys, so if they must stop they can lock the car with the air conditioner running for a short time (while keeping the window slightly open as a precaution).

If you think your dog is overheating, Grebe advises that you quickly move him to a cool place and immediately spray cool (not cold or icy) water on the coat, ensuring it reaches the skin. Cold water tends to constrict the surface blood vessels in the skin and this reduces, instead of increases, heat loss.

Use a fan to draw heat from the blood at the body surface, or fan the dog yourself if an electric fan is unavailable.

Wipe the face and muzzle with cool water, and as soon as possible take him to an emergency clinic. Remember, if you are sweating, your dog is already uncomfortable and must work much harder to cool down by panting.

Observe your dog carefully, and if you notice symptoms of overheating, don’t wait until it’s too late. Take precautions to prevent overheating, but if that fails, take immediate action to prevent a tragedy.

Related article: How to Keep Your Dog Cool in Extreme Heat Without Air Conditioning
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