The Denver-Aurora area ranks third when it comes to gauging the nation's "fittest cities," reports the American College of Sports Medicine's American Fitness Index. Only Washington D.C., and Minneapolis-St. Paul rank higher than Denver in the annual "snapshot of the state of health and fitness in America's 50 most populous metropolitan areas." The index takes into account issues such as levels of chronic disease, health-care access, and policies supporting physical activity, writes the Denver Business Journal. In other words, cities that score high have amenities such as parks and bike trails-- among other advantages, notes USA Today. They also have a higher percentage of people who don't smoke, eat well, and exercise regularly. Boston and San Francisco rounded out the top five, while the nation's largest cities--New York, Chicago, and Los Angeles--ranked 22nd, 25th, and 30th, respectively.