Background : Cardiopulmonary Exercise Testing (CPET) is the gold standard for the integrated assessment of cardiovascular, respiratory, and metabolic function during exercise. Physiological responses may vary according to body posture: upright (UP), supine (SP), and semi-recumbent (SR). Previous studies have reported differences in CPET parameters (VO₂peak, VE/VCO₂ slope, anaerobic…