Obviously, it is going to be important to have extracurricular activities that are directly relevant to the medical profession (e.g., research, shadowing, etc.). However, if you love and seriously engage in an unrelated activity (e.g., yoga, mountain climbing, etc.), that activity can be important as well. The key in my opinion is to demonstrate passion for those activities and to show how they make you a happier/better person. I firmly believe that most medical schools want well-rounded, passionate, likable and happy students. Often I think about applications as follows: If you were watching a movie about the "character" portrayed in the application, would you root for that character? If the answer is "yes", the applicant is doing something right.