During a CPET, the individual performs exercise on either a cycle ergometer or a treadmill while the workload gradually increases according to a predefined protocol. Throughout the test, physiological responses are continuously monitored.

During the test, physiological responses are continuously monitored. In addition to heart rate, electrocardiography (ECG) and blood pressure, some CPET protocols also include peripheral oxygen saturation (SpO₂) monitoring. The participant wears a face mask or mouthpiece connected to a metabolic measurement system, which continuously analyses inhaled and exhaled gases on a breath-by-breath basis.

The test continues until the predefined endpoint is reached, which is often symptom-limited maximal effort or another clinically appropriate stopping criterion. Following exercise, the participant enters a recovery phase while monitoring continues until physiological values begin to return towards baseline.

Traditional exercise tests primarily evaluate the cardiovascular response to physical activity. While these tests provide valuable clinical information, they do not directly assess respiratory gas exchange.

CPET adds respiratory gas analysis to conventional exercise testing, allowing multiple physiological systems to be evaluated simultaneously. Rather than examining the heart or lungs independently, CPET assesses how the cardiovascular, pulmonary and muscular systems function together during increasing exercise intensity.

This integrated approach provides a more complete understanding of the body’s response to exercise and distinguishes CPET from conventional exercise stress testing.

Exercise depends on the coordinated interaction of the cardiovascular, respiratory and muscular systems. A cardiopulmonary exercise test is designed to evaluate this integrated response under controlled conditions using objective physiological measurements.

By combining progressively increasing exercise with continuous physiological monitoring and respiratory gas analysis, CPET provides a comprehensive assessment of exercise performance. For this reason, it is widely used in healthcare, rehabilitation, sports medicine and research when an objective evaluation of exercise physiology is required.

A cardiopulmonary exercise test is a comprehensive, non-invasive assessment of the body’s response to physical exercise. By combining controlled exercise with continuous monitoring of physiological responses and breath-by-breath gas analysis, CPET evaluates how multiple body systems work together during increasing physical effort.

In this article, we introduced the fundamentals of cardiopulmonary exercise testing. In subsequent articles, we will explore how CPET differs from conventional exercise testing, which physiological variables are measured, how results are interpreted, and when CPET is used in clinical practice.