1. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas and The University of Texas Southwestern Medical Center , 7232 Greenville Ave., Suite 435, Dallas, Texas 75231 , USA
2. Department of Cardiology, Royal Brompton and Harefield NHS Foundation Trust , London , UK
3. Faculty of Medicine, National Heart and Lung Institute, Imperial College , London , UK
4. Cardiovascular Research Laboratory, Biomedical Research Foundation, Academy of Athens , Athens , Greece