From the Cardiovascular Performance Program, Massachusetts General Hospital, Boston (R.B.W., J.R.D., J.L., M.M.W., G.D.L., A.M.H., M.H.P., A.L.B.); Harvard University Health Services, Cambridge, MA (R.B.W., F.W., B.B., A.L.B.); and Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, United Kingdom (E.S., R.S.). (At 2015-12)