Main study parameters/endpoints: The primary outcome is the change in peakVO2 between patients in the sports participation group, and the control group. Secondary outcome measures are change in NYHA functional class, quality of life, and NT-proBNP levels. The primary safety outcome is the composite of all hospitalizations, and all deaths during, or within three hours after exercise. The secondary safety outcome is the composite of all exercise related injuries for which medical attention is sought.