Living a long time is appealing, but only if the extra years can be healthy ones. Dr. Mark Liponis, medical director of the Canyon Ranch Resorts, says paying attention to the immune system can make a big difference. We discuss his thesis that managing the immune system to keep it from becoming overactive can slow down the aging process. He shares his seven steps for a healthier life–and we find out what barnyard animals have to do with it. Guest: Mark Liponis, MD, Corporate Medical Director of Canyon Ranch Resorts and author of UltraLongevity: The Seven-Step Program for a Younger, Healthier You. His previous book, with Dr. Mark Hyman, was Ultraprevention.