Exercise testing provides information on physical capacity during exercise in addition to spirometric measures of lung function or assessment on treadmills or ergonomic cycle. The "gold standard" assessment of exercise tolerance is measured in the laboratory using treadmills or ergonomic cycle but the necessary equipment is expensive and may not be readily accessible; such tests require people used to work with children. Walking tests are field tests providing a valid and easily accessible method of measuring function-limited exercise tolerance in patients with respiratory or cardiac chronic diseases. These walking tests are non-threatening, inexpensive, easy to perform and to understand for children. Walking tests performed in daily practice are the following: "time-based" tests (2-, 6- or 12-min walking test), 3-min step test (on a step) and the shuttle walking test. It may be a useful measure to assess therapeutic intervention and provide information on the prognosis. They are simple and safe methods to evaluate quality of life in these patients.