Should you wait an hour after eating before swimming? Do you lose most of your body heat through your head? Will lifting something heavy give you a hernia? Dr. Aaron Carroll, associate professor of pediatrics and director of the Center for Health Policy and Professionalism at the Indiana University School of Medicine and co-author of Don't Swallow Your Gum! Myths, Half-Truths, and Outright Lies About Your Body and Health, takes on some persistent medical misconceptions.