Walking my dog in the heat

I have a 9 year old chocolate lab named Molly. She loves going for walks, but sometimes it is 28-30 degrees Celsius outside, and when you add in the humidex, it feels like 37+ celsius. She makes it fine during the walk, but it sometimes takes her 2-3 hours to totally cool down. She just pants. Is this okay?

Answer from Dr. Gaylord Brown:
It is important to know your pet’s physical condition when exercising and not over do it. When you are walking with your dog you know how you feel and what you need to do to battle the heat. Rest as need under shade and take water for your dog to keep hydrated. The panting is required to cool down so do not be alarmed.