1. From the Laboratory of Physiology, Faculty of Medicine (A.V.O., R.N.), Laboratory of Physiology, Institute of Sports and Physiotherapy (J.J.M.), Department of Intensive Care of the Erasme Hospital (C.M.), Free University of Brussels, Belgium, Medical Clinic VII, Sports Medicine, University of Heidelberg (H.M.), Germany; and the Department of Internal Medicine of the University Hospital (M.M.), Zürich, Switzerland.