Count on Yoga - 30 reasons to do yoga

6. Tone Zone

It's well documented that weight-bearing exercise strengthens bones and helps ward off osteoporosis. Many postures in yoga require that you lift your own weight. And some, like Downward- and Upward-Facing Dog, help strengthen the arm bones, which are particularly vulnerable to osteoporotic fractures. In an unpublished study conducted at California State University, yoga practice increased bone density in the vertebrae. Yoga's ability to lower levels of the stress hormone, cortisol, may help keep calcium in the bones.