Preventing and managing heat stroke in dogs
The number one rule is: Know your dogs.
I have seen dogs unable to stand and in shock on a 45°F day after running on snow and I have seen dogs race hard at 50°F over a much longer distance, only lightly panting. I have seen short-coated white dogs overheat while the black dog standing next to them on the same team is warm, but not in trouble. Some dogs foam like rabid animals and are fine, others aren’t.
The best treatment is prevention. PLEASE don’t get sucked into the trap of having your buddy/neighbor/competitor telling you that they are going 5.5 miles at 50°F and try to convince you that your dog(s) can do it, too. Dogs that have a fitness base can tolerate heat better than dogs that don’t; even two weeks of training helps them cope better and very fit dogs in the spring can handle it best. Dogs at proper body weight can cope better than overweight dogs. By the time you get into early November, you should have been able to observe which individuals come back the most warm on short training runs.
Dogs who are warm, but not in trouble:
• Are panting rapidly
• Have normal mentation (that is, they are watching what you are doing as you unhook/water the team etc.)
• May be either standing or lying down to cool themselves. If standing, they are strong on their feet and not wobbly
• May or may not be foamy with saliva
• If you look into their open mouth, you usually cannot look down the trachea and see the rings
Unfortunately determining trouble from the viewpoint of the runners or a cart while running dogs is not always obvious. Some clues for overheating are:
• Running with the chin more elevated than normal. This is the most frequent sign of trouble, but it can be subtle. Some dogs run like this all the time.
• Stride length shortening
• Not working hard
• Trouble moving forward in a straight line, swaying, tripping
Those are signs but they don’t always manifest. I have seen dogs that do NONE of the above and will continue to act as if they are just fine… but when you stop you will see they are in trouble:
• Standing with legs braced like a saw horse, they are often not strong on their feet and will wobble or sway
• Collapsed and too weak to stand
• Abnormal mentation, seem “glazed over” and not responsive to normal activity and may not be response to “noxious stimuli” (for example, obtaining rectal temperature with a thermometer)
• Panting is very deep, loud, mouth is wide open and you can see the rings of the trachea.
Over 107°F was the “tipping point” for life threatening heat stroke based on studies done by musher-on-hiatus Rob Downey and the late Dave Kronfeld at UPenn. I have seen dogs showing life threatening complications at 106°F. I am aware of, but haven’t seen, dogs who are NOT in trouble at 107°F, but I wouldn’t be comfortable telling you that’s okay. Also, dogs who have previous overheated have permanently damaged heat control regulation and can overheat at 104.5°F, so while the thermometer can be helpful, it is far better to look at the patient (the dog!!).
If possible, get a rectal thermometer and monitor the dog’s temperature every few minutes. It is critical to NOT overcool the dog as this will do as much damage as the heat stroke. STOP ALL COOLING when the dog gets down to 103.5°F as their temperature will continue to drop afterwards, especially if they are in shock. If you have no thermometer, use tepid/cool water (NOT cold and not ice packs) and a breeze, natural or a fan if available, and get veterinary attention. Draping a wet towel is discouraged because it insulates. Ice packs are discouraged because they can lead to skin damage in shocky animals. Piling them near, but not too near the mouth of a down dog will help cool the air they pant (just don’t obstruct air movement).
If your dog collapsed, did not revive mentally very rapidly as his body was cooled, is unable stand as the body cooled, or has very small pinpoint or small blotchy red patches on the belly, please get her to a vet. These dogs can die if not treated appropriately for shock from renal failure, disseminated intravascular coagulation, or hypoglycemia.
What is shock? Shock is a broad term used to describe any condition in which there is poor blood perfusion to body tissues resulting in decreased oxygenation and death of cells. Many things can cause this, but in heat stroke, the body tries to protect the core temperature of the brain by adjusting blood flow in such a way that other tissues get deprived of oxygen, which works great as a short term solution, but if the correction isn’t made quickly (stop running, start cooling) then the downward spiral of shock from heat stroke begins.