Why do a cardiopulmonary exercise test?

This chapter describes how a maximal cardiopulmonary exercise test (CPET) assesses the exercise capacity of an individual. It identifies whether exercise is limited by the heart or lungs, or by another factor. The test can be used to elucidate the cause of symptoms such as breathlessness. By quantifying exercise capacity, a CPET can be used as a tool to plan physical training. Information from a CPET helps quantify the risk of a surgical intervention and is used in planning post-operative care. Performance in a CPET is a predictor of subsequent mortality. A CPET should be preceded by a full clinical history and a thorough clinical examination. The test is best interpreted alongside the results of simple preliminary investigations.