He studied medicine at the University of Amsterdam where he graduated as an M.D. in 1986; he subsequently did two years of clinical work before coming to Geneva at the Faculty of medicine of the University of Geneva to work as a research assistant in the lab of Paolo Cerretelli; Ph.D. (on the topic of exercise limitation at high altitude) 1994 at the Free University of Amsterdam; then he spent two years in the lab of Peter Macklem at McGill University in Montreal, Canada, working on respiratory mechanics during exercise in healthy subjects and in a human model of chronic obstructive pulmonary disease; subsequently returned to Geneva where he continued research in the field of exercise physiology but also worked on IT technology for learning and medical education; in October 2002 he was appointed professor of exercise sciences at the Faculty of medicine of the University of Geneva in the department "Unite de Developpement et de Recherche en Education Medicale"; one of five candidates from the Netherlands in the 1992 ESA selection (only André Kuipers was selected as an astronaut); hobbies: to read and be out-doors, sports activities include (mountain) running, cross-country skiing, telemark skiing and rock/alpine climbing.