Exercise testing is frequently used for evaluation of exercise capacity and cardiopulmonary function in children with congenital cardiac defects or acquired cardiac disease. An often-used protocol for treadmill testing is the Bruce protocol (Bruce et aI., 1973), which was originally designed for adults (van der Cammen-van Zjip et aI., 2010). Although exercise testing is widely used in children, there is no agreement in specific practice guidelines for paediatric exercise testing (Chang et aI., 2006).