“You have to try to prevent the loss of muscle and bone, and while cardio will make your heart and lungs fitter, it won’t increase—and might not even prevent—loss of muscle mass,” says Wendy Kohrt, an exercise physiologist and a professor of geriatric medicine at the University of Colorado Health Sciences Center. “The research is preliminary, but it suggests that those who do resistance training seem to preserve the level of lean mass they had before menopause.”