Comparison of cardiorespiratory responses between treadmill and bicycle ergometer exercise

The talk test (TT) is a subjective, self-administered method used to gauge aerobic exercise intensity based on a person's ability to speak comfortably during physical activity. This study aimed to validate the TT by examining its relationship with physiological markers collected during cardiopulmonary exercise testing (CPX) on both a treadmill and stationary bicycle in healthy adults. Twenty-two healthy participants (17 males and 5 females), with no known musculoskeletal, cardiovascular, or pulmonary conditions, completed two exercise sessions-one on a treadmill and another on a stationary bicycle. Each session was structured into three stages of increasing intensity based on the TT. During each stage, various psychophysiological and cardiorespiratory variables were measured, including heart rate, rating of perceived exertion, metabolic equivalents, arterial oxygen saturation, respiratory rate, minute ventilation, oxygen uptake, carbon dioxide production, respiratory exchange ratio, and ventilatory threshold. Significant differences were found across the three TT stages for all measured variables, with values increasing linearly as intensity progressed. However, no significant differences were observed between exercise modalities (treadmill vs. bicycle) or in the interaction between TT stages and modality. The findings support the TT as a valid indicator of exercise intensity, correlating well with physiological responses measured during CPX. The consistency across both exercise modalities suggests that TT is a practical, effective tool for guiding aerobic exercise intensity, particularly in clinical and rehabilitation settings.