Cardiopulmonary Exercise Testing

Test Interpretation

The American Thoracic Society and European Respiratory Society recommend verifying adequate effort (RER >1.10) and ensuring appropriate protocol selection (8-12 minute test duration ideal) to assess test quality and effort, and evaluating trending phenomena throughout exercise (submaximal to peak) and assessing graphical relationships (VE vs. VCO₂, VO₂ vs. work rate) to analyze exercise patterns 1, 2
The American Heart Association recommends terminating CPET for any of the following: decrease in ventricular rate with increasing workload with symptoms of insufficient cardiac output, failure of heart rate to increase with exercise with symptoms, progressive fall in systolic blood pressure with increasing workload, severe hypertension (>250 mmHg systolic or >125 mmHg diastolic), intolerable dyspnea, symptomatic tachycardia, or progressive fall in oxygen saturation to <90% or a 10-point drop from resting saturation with symptoms 3

The American Journal of Respiratory and Critical Care Medicine characterizes exercise limitations as follows:

The interpretation should conclude with quantification of exercise capacity (normal, mild, moderate, or severe impairment), primary limitation (cardiac, pulmonary, peripheral, or deconditioning), specific pathophysiologic mechanisms contributing to exercise limitation, and clinical correlation with patient symptoms and presentation, as recommended by the American Thoracic Society 1
Potential causes of progressive shortness of breath include:
Recommended diagnostic tests include:
A thorough medical history, including exercise tolerance and impact on daily activities, should be taken to help determine the underlying etiology of progressive shortness of breath, and cardiopulmonary exercise testing (CPET) is the gold standard to differentiate between cardiac, pulmonary, and other causes of exertional shortness of breath, providing objective measurement of exercise capacity (VO2max), ventilatory efficiency (VE/VCO2), oxygen pulse, breathing reserve, and evidence of exercise-induced hypoxemia, as recommended by the American Thoracic Society 4, 1
The American Thoracic Society guidelines emphasize that target heart rate achievement is critical, as submaximal tests (below 85% of predicted maximum heart rate) may miss significant pathology, and shortness of breath during exercise can represent cardiac disease, pulmonary disease, deconditioning, or a combination of factors, highlighting the need for a systematic diagnostic approach 1, 12