Click here tofind out more!If you're reading this article sitting down—the position we all hold more than any other, for an average of 8.9 hours a day—stop and take stock of how your body feels. Is there an ache in your lower back? A light numbness in your rear and lower thigh? Are you feeling a little down? These symptoms are all normal, and they're not good. They may well be caused by doing precisely what you're doing—sitting. New research in the diverse fields of epidemiology, molecular biology, biomechanics, and physiology is converging toward a startling conclusion: Sitting is a public-health risk. And exercising doesn't offset it. "People need to understand that the qualitative mechanisms of sitting are completely different from walking or exercising," says University of Missouri microbiologist Marc Hamilton. "Sitting too much is not the same as exercising too little. They do completely different things to the body."