Dear Dr. Dog: As summer approaches, I worry that a lot of dogs are going to be left in hot cars or otherwise exposed to dangerously high temperatures. Can you explain the risks involved?
An over-heated dog? Sounds like all you need to do is let him cool down for a while. Actually, heatstroke is a lot more serious than that and can be fatal. The sooner it is diagnosed and corrective efforts are begun, the better chance a dog has of recovering. Needless to say, preventing heatstroke in the first place is highly recommended.
Heatstroke is the syndrome of decline in mental status and damage to internal organs caused when the body temperature rises too high. Sustained body temperatures of 105-106 have been reported to cause permanent organ damage, and if body temperature rises to 109, direct thermal damage to internal organs occurs quickly. This can begin a fatal cascade of organ malfunctions.
You are probably aware that dogs have a different method of cooling themselves than we do. They do not perspire, which is otherwise a very efficient mechanism by which an animal can cool itself. In humans, when body temperature rises a mere 1/10 of a degree, we begin to perspire through much of our skin area. Our canine friends perspire minimally, only from the pads of their feet and the tips of their noses. The only meaningful way they can actively cool themselves is by evaporating water from the inside of their noses and mouths by panting.
While this is adequate under most circumstances, it is not as efficient as perspiring, and therefore dogs are at risk of heatstroke during prolonged exposure to hot weather. Dogs with shorter noses and mouths (pugs, bulldogs, and so on) are at the greatest risk because, in part, of the smaller surface area inside their noses and mouths from which to evaporate water when panting.
One of the tragic aspects of this condition is that even active and healthy dogs acclimated to exercising in hot weather can be stricken unexpectedly. Veterinarians speculate that this occurs due to a dangerous combination of high ambient temperature, sufficient humidity, and the dog’s state of hydration, which varies from day to day. It may be that the active, healthy dog that succumbs one day to heatstroke while on a routine hike has simply been the victim of a “perfect storm” of temperature, humidity, and dehydration.
Please do not be lulled into a sense of security about your dog’s ability to handle the heat based on his past successful outings on hot days. There is no precise outdoor temperature above which heatstroke can be predicted to occur. Your best guide is common sense: if it’s a hot day for you, then it’s an even hotter day for your furry friend who can’t sweat.
The most tragic example of heatstroke is when a dog is inadvertently left outdoors on a hot day without adequate shade and water, or is left in an enclosed area (a garage or car) without adequate ventilation. Temperatures inside a parked car rise quickly to over 100 degrees in the sun, even with the windows partly down. And a car that is parked in the shade right now may soon be in full sun. There is only one intelligent piece of advice here: never, ever, ever, leave your dog in a parked car.
What can happen to a dog suffering from heatstroke? Just for starters: liver failure, kidney failure, brain damage, muscle damage, damage to blood vessels throughout the body, massive intestinal hemorrhaging, blood clots, and death. It is a very, very serious condition and is complicated and difficult to treat if severe.
I don’t want to scare you into locking your dog in an air-conditioned house all summer, but I really DO want to scare you enough to be conscious of this serious condition any time you take you dog outdoors for an extended period of time in the next few months.
What should you do to avoid heatstroke? If you must take your dogs out during the heat of the day, be sure they are well hydrated. Give them plenty of opportunity to drink before going out, and take along water supplies. I also recommend carrying a spray bottle so you can “mist” your dog’s face frequently in hot weather.
A dog suffering from heatstroke will often pant rapidly, drool, vomit, and become weak or mentally unresponsive. If you think your dog may be suffering from heatstroke, immediately get him out of the sun and to an emergency veterinary clinic. If possible, douse him with cool (not cold) water. Place a fan in front of him and apply cold packs in his groin area and under his “arms” to help cool the blood that is returning from the limbs to the interior of his body.
However, do not soak the dog in very cold water. This could cause the blood vessels in the skin to constrict (a natural reaction to prevent further heat loss), thereby trapping the heat inside the body’s core — precisely what you want to avoid.
My best advice is to keep safe and cool this summer. Walk your dog in the early morning or evening, be sure he has plenty of shade, water, and ventilation if he is outside during the day, and never leave him in a parked car.
And remember: Don’t be fooled into thinking that your dogs are fine simply because they have handled hot weather well in the past. Heatstroke is an unpredictable occurrence, and one that can have tragic consequences if not detected and corrected immediately.
Dr. Franklin Utchen has been practicing veterinary medicine in San Ramon since 1989 and currently co-owns Bishop Ranch Veterinary Center & Urgent Care. His special interests include Orthopedic and Soft Tissue Surgery, Internal Medicine, Emergency/Critical Care, Dentistry, and Anesthesiology/Pain Management. For questions or comments email bishopranchvets@yahoo.com. (See the display ad for Bishop Ranch Veterinary Center on page 10.)
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