Paediatric exercise testing

Spirometry and other lung function tests can be used to diagnose and guide therapy in children with lung diseases. However, they only assess resting lung function indices. Cardiopulmonary exercise testing (CPET) allows evaluation of overall exercise capacity, both in healthy children and in those with chronic disease. During exercise testing, functional deficits that were not apparent during conventional pulmonary function testing may be identified. Indications for exercise testing include assessment of exercise capacity, detection of adverse reactions to exercise, such as exercise-induced bronchoconstriction, arrhythmia or hypoxia, and evaluation of the functional impact of chronic illnesses on children. The results of exercise tests can be used as a guide to prescribing safe and individual exercise programmes. They can also provide confidence to the child, caregivers, teachers and primary care physicians that it is safe for the child to exercise. Maximal aerobic exercise capacity can be determined directly by the measurement of maximal or peak oxygen uptake during formal CPET on a treadmill or a cycle ergometer. It can also be assessed indirectly by measuring heart rate or power output during maximal or submaximal exercise, and can be estimated in field tests. Field tests are simple to perform and inexpensive and are often used in epidemiological surveys, in the rehabilitation setting or in advanced disease. Their main limitation is that they are difficult to standardise. Formal CPET allows assessment of various ventilation parameters such as oxygen uptake, ventilatory anaerobic threshold and flow limitation. It is particularly suited to determine the aetiology of impaired exercise tolerance. There is no “best” exercise test as such. Whichever test is preferred depends not only on the indication and the clinical question, but also on the condition of the subject tested, the experience of the tester with a specific protocol, safety issues and financial resources