1 From Cardiovascular Performance Program, Massachusetts General Hospital, Boston (A.L.B.); and Institute for Exercise and Environmental Medicine, Texas Health Resources and the University of Texas Southwestern, Dallas (B.D.L.). abaggish@partners.org.
2 From Cardiovascular Performance Program, Massachusetts General Hospital, Boston (A.L.B.); and Institute for Exercise and Environmental Medicine, Texas Health Resources and the University of Texas Southwestern, Dallas (B.D.L.).