Summer Heat Stroke Danger for Dogs

Tracy Libby
Heat Stroke in DogsSwimming is one way to avoid heat stroke on a hot summer day. (Photo: © Tracy Libby Photography)

When sunshine taps me on the shoulder, I have to head outdoors with my dogs. Whether we're swimming, hiking or just hanging out under the trees with the breeze blowing and the birds singing—summer is one of my favorite seasons. But hot weather spells trouble for dogs because heat and humidity can quickly raise a dog's body temperature to dangerous, life-threatening levels.

While heat-related illnesses are among the most common summer canine ailments, they need not be. Armed with a basic understanding of how and why dogs overheat, as well as a good dose of commonsense, you can keep your dog safe as summer temperatures sizzle.

Body Basics

A dog's average body temperature is 101.5º F (38.6º C), with a normal range between 100º and 102º (37º C and 39º C). While temperatures can vary throughout a dog’s body, the core temperature is what a dog’s body uses to maintain constant internal conditions, also known as homeostatic condition, and includes blood pressure, blood chemistry, and body temperature.

Unlike humans, dogs don't sweat (except to a minor degree through their foot pads) so they don't tolerate high temperatures as well as humans do. A dog's primary cooling mechanisms is panting, which exchanges warm air for cool air. However, when air temperatures are close to a dog's body temperature, cooling by panting is not an efficient process.

When a dog’s normal body mechanisms can't keep his temperature within a safe range—heat induced illnesses occur. Heat exhaustion, heat prostration, and heat stroke are increasingly severe levels of the same basic condition. While the first two are serious and can take a serious toll on a dog's health, heat stroke kills dogs. Dogs with moderate heat stroke (a body temperature of 104°) can recover if given prompt first aid and veterinary care. Severe heat stroke occurs when a dog’s body temperatures is over 106º F (41º C), and is considered a life-threatening medical emergency.

Interestingly, research suggests that longer exposure times at a certain temperature might have more detrimental effects than shorter periods of exposure at a higher temperature. Dogs suffering from mild or moderate heat stroke will normally exhibit some or all of the following symptoms: rapid panting, increased respiratory rate, increased heart rate, restlessness, excess salivation, vomiting, and dehydration.

As heat dissipation fails and your dog's body temperature increases, symptoms become even more severe including; weakness, collapsing and/or inability to stand up, red or pale gums, thick and sticky saliva, vomiting (with or without blood), diarrhea, shock, fainting, and coma.

Once your dog gets into real trouble, it may be too late. When a critical temperature is reached, multiple organ system dysfunction occurs and dogs begins to suffer irreversible damage to the kidneys, liver, gastrointestinal tract, heart, and brain. An estimated 50 percent of dogs do not survive, with death generally happening within the first 24 hours of the incident. For dogs who survive 48 hours of hospitalization, the outcome is usually good.

Dogs at Higher Risk

Some dogs are at a higher risk of developing heat stroke including: brachycephalic dogs (flat- or short-nosed dogs such as Pugs, Boston Terriers, Pekingese, Boxers, Bulldogs, Shih Tzus, and so forth because they don't breathe as efficiently as long-nosed dogs), older dogs, puppies, sick dogs - including those with underlying heart and lung diseases, obese dogs, dogs not acclimated to hot weather, and dogs with a previous history of heat-related disease.

What You Can Do

Recognizing the symptoms of heat stroke and responding quickly are essential for the best possible outcome. If your dog is experiencing symptoms of heatstroke:

  • move him out of direct sunlight and to a cool environment immediately, such as a shaded area or air-conditioned room or car
  • lower his temperature by applying cool water to his body—stomach, inner thighs, neck, head, and foot pads—with a shower, hose, wet towels or any other source of cool water that is handy. Do not use cold water or ice, as it causes the blood vessels to constrict, which slows blood flow; thus slowing the cooling process and possibly exacerbating the situation.
  • offer him small amounts of water or a rehydrating solution. Do not force water or allow him to drink too much water too rapidly, as it could lead to choking, vomiting or bloat.
  • seek immediate veterinary attention

Preventing Heat Stroke

The best defense against heat stroke is to monitor your dog and his activities, as most, if not all, cases are entirely preventable.

  • Do not place him in a situation where he can become overheated.
  • Provide your dog with access to shade and fresh water while outdoors.
  • Limit his exercise, such as running, playing, training, etc., to the cooler parts of the day.

Your dog need not run around like a wild banshee in the heat of the day to be susceptible to heat stroke. Non-exertion heat stroke most commonly occurs when dogs are confined in an overheated enclosure, such as an automobile, or when they are confined outdoors during warm weather or high humidity and deprived of water or shade.

Never leave your dog unattended in a car. On a sunny day when ambient temperatures are 85º F (30º C) it can take less than 10 minutes for the internal temperature of a parked vehicle to reach 102° F (30° C) and less than 30 minutes to reach 120° (49° C) even with all the windows partly open. A dog can suffer irreparable brain damage or death if his body temperature rises to 107º F (41.6º C). In the amount of time it takes to make a quick trip into the grocery store, your dog could be exposed to life-threatening temperatures.

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