A message from the Humane Society of the United States about heat and exercise for your pet:
Limit your pet's outdoor exercise on hot days. Adjust intensity and duration of exercise in accordance with the temperature. On very hot days, limit exercise to early morning or evening hours, and be especially careful with pets with white-colored ears, who are more susceptible to skin cancer, and short-nosed pets, who typically have difficulty breathing. Asphalt gets very hot and can burn your pet's paws, so walk your dog on the grass if possible. Always carry water with you to keep your dog from dehydrating.
To read more, go to: www.humanesociety.org/animals/resources/tips/pets_safe_heat_wave.html