For Lisa Rinna, exercise is the key to her positive mental outlook. "That's why I work [out] so hard – because if you don't feel good about your body, you don't feel good about anything," says the actress, who teaches a dance-aerobics class with her former Dancing with the Stars partner Louis van Amstel in Sherman Oaks, Calif. "I do whatever it takes so that I feel good – not just how I look, but how I feel inside." Read about how running can have a calming effect on Health.com. – Shruti Dhalwala