A Call for Contextualization: Is Cardiopulmonary Exercise Testing the Gold Standard for Exercise Capacity?

Cardiopulmonary exercise testing (CPET) is widely regarded as the gold standard for assessing exercise capacity. However, this designation is increasingly challenged by both conceptual and practical limitations. CPET outcomes are highly protocol-dependent and obtained under controlled laboratory conditions that fail to replicate the biomechanics, environmental demands, and motivational context of real competition. In addition, its reliance on specialized equipment, technical expertise, and laboratory infrastructure imposes economic and logistical constraints that limit accessibility and scalability. In contrast, advances in wearable technology have enabled the routine collection of field-based performance data, including power output, race results, and power-duration relationships. These metrics provide a direct, ecologically valid assessment of performance, inherently integrating the effects of fatigue, environmental variability, and task-specific demands. As such, they may offer a more relevant characterization of exercise capacity in athletic populations. This perspective argues that field-derived performance metrics should be considered a viable alternative to CPET for assessing exercise capacity in sport settings. We propose that rather than relying on laboratory-based proxies, greater emphasis should be placed on direct measurements of performance obtained in real-world conditions. Such a shift may improve the ecological validity, accessibility, and practical relevance of athlete evaluation in modern sports science and coaching.