Interactive worksheet
RER Peak Index (Respiratory Exchange Ratio) Calculator
RER Peak Index (Respiratory Exchange Ratio): Explanation and Clinical Context The RER Peak Index is calculated as the ratio of carbon dioxide production (VCO₂) to oxygen consumption (VO₂) at peak exercise. It serves as an objective measure of exercise intensity and maximal effort during cardiopulmonary exercise testing (CPET). A normal RER at rest is approximately 0.8, reflecting primarily fat metabolism. During prog