Most dogs know when they’re getting too hot and will slow down or look for a cool resting area. If you sense that your friend is reluctant to engage in activities on a hot day, it’s best to let him be. Remember, the dog who loves playing so much that he always refuses to stop is the one who generally encounters overheating problems. The best way to prevent them entirely is to make sure Fido is never far from cool water and shade. If the heat and humidity are making you uncomfortable, assume your dog is uncomfortable too, and encourage him to slow down—or even to jump into a kiddie pool if there’s one around. And you can always simply spray him with the hose. If your dog gets overheated to the point where he collapses, move him immediately to a cool area, wet him down with cool water (using a hose, sponge, or washcloth), and get him to a vet.