1. From the Heliomare Research and Development and Heliomare Rehabilitation Center (J.A.A., T.V.B., C.A.M.V.B.), Wijk aan Zee, the Netherlands; Department of Psychology (J.A.A., W.F.H.), University of Amsterdam, Amsterdam, the Netherlands; Department of Pulmonary Medicine (J.G.V.D.A.), Medical Centre Alkmaar, Alkmaar, the Netherlands.