Prof Kathy Sietsema (Emeritus Professor of Medicine, Harbor-UCLA Medical Center; UCLA School of Medicine)

Cardiopulmonary exercise testing (CPET) measures blood pressure, heart rate, electrocardiogram, breathing and gas exchange during graded exercise. A key parameter is oxygen uptake (VO₂), which reflects metabolic demand and defines maximal exercise capacity. Peak VO₂ is a global indicator of health, fitness and survival across populations, including those with heart failure, congenital heart or lung disease, and surgical risk. CPET supports diagnosis of unexplained symptoms, personalised assessment of known conditions, and rehabilitation planning. Its ability to profile impairment, identify limiting factors, and guide tailored interventions makes CPET valuable in both clinical decision-making and patient care.