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.