1 1National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD; 2National Institute on Aging, National Institutes of Health, Bethesda, MD; 3Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA; and 4Arnold School of Public Health, University of South Carolina, Columbia, SC.