New and sealed Two Experts Set the Pace for Optimum Health with This Take-Anywhere Walking Workout Session. Andrew Weil, M.D. Mark Fenton. Most of us enjoy walking, but not everyone knows how to turn this simple exercise into one of the most powerful self-healing tools known to medicine. On Walking: The Secret to Optimum Health, Dr. Andrew Weil joins Mark Fenton, the nation's foremost expert on walking, for an invigorating 2-CD program that gives listeners all the tools needed to begin a daily walking practice. On Part One, Dr. Weil and Mark Fenton explain the proven ways in which walking helps you look and feel younger, reduce stress, improve immune function, achieve your ideal weight, and more. On Part Two, listeners get walking with a fully programmable workout that features two warm-up options and five intensifying sessions, paced by cadence cues and motivating tips for each phase.