No one's ever called you a couch potato or told you to cheer up. Your fun-loving days are filled with running and biking adventures that push you hard; strap on the Polar RCX3 Heart Rate Monitor to maximize your playtime and thrill yourself with the results. Optimize every ride and run and delight in the instant feedback and feel the progress from your oxygen-pumped brain to your stronger quads. You've heard the phrase, "Train smarter not harder," but you can train funner, too.