Heat Stroke in Dogs

By Nutrena

Heat stroke occurs when a dog’s body temperature rises above 106°F (41°C). It begins with heat exhaustion when the body temperature rises to between 103°F and 105°F. A dog’s normal body temperature is 101°F to 102.5°F. It should be noted that heat exhaustion/stroke is different from fever which is a normal internal physiologic process secondary to infection or inflammation. Heat stroke is the result of an external stressor on the body and is not a normal physiologic process but the evolutionary lack of a physiological process, namely the ability to perspire.

Dogs do not have sweat glands in their skin and therefore must cool by panting. On a day when there is less than a 10-15-degree temperature differential between their breath and the air for heat exchange, this is not a very effective cooling method. The few sweat glands they have in their feet are minimally effective at heat dissipation. When panting is not enough to keep cool, their body temperature rises leading to heat stroke, shock and cardiac arrest.

Signs of heat exhaustion and heat stroke include the following:

  • Panting
  • Dehydration
  • Excessive drooling
  • Bright red tongue
  • Blue, red or pale gums (normally pink)
  • Production of only small amounts of urine or no urine
  • Rapid heart and/or irregular heart beats
  • Increased body temperature – above 103° F (39° C)
  • Vomiting (with or without blood present)
  • Passage of red blood in the bowel movement or black, tarry stools
  • Changes in mental status
  • Muscle tremors
  • Lack of coordination, wobbly
  • Small, pinpoint areas of bleeding on the gums, eyes or non-haired skin

One of the very early, subtle signs can be lack of responsiveness to commands. Dogs tend to want to please their owners and respond quickly to commands. If you call your dog’s name and he does not look at you or come to you but rather walks away, this can be a very early, recognizable sign of heat exhaustion. This should be an immediate cue to get him out of the heat.

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