Isocaloric Supplements of Whey Protein and Carbohydrates on Responses of Cardiorespiratory and Metabolic Systems and Blood Glucose Levels during Acute Progressive Exhaustive Exercises. JEPonline 2023;26(3):1-14. The purpose of this study was to determine the effects of isocaloric supplements of whey protein and carbohydrate on physiologic functions and performance. Three separated randomized ingestions of whey protein (PRO), carbohydrate (CHO), and mixing of PRO-CHO (MIX) were provided to healthy males prior to performing progressive exercises to exhaustion. Blood glucose levels and physiological variables of the cardiorespiratory and metabolic functions were determined. Higher blood glucose was detected only in the ingestion of CHO. Most of gas exchange and cardiorespiratory variables measured during exercise were similar in all trails, except for the lower diastolic BP in PRO than in CHO and MIX throughout the test. MIX induced a higher VO2 peak than did the other trials. In conclusion, immediate isocaloric ingestions of CHO, PRO, and MIX had exerted no impact on cardiorespiratory functions during high physical demands. Only the ingestion of CHO showed metabolic changes via blood glucose level; whereas, the ingestion of MIX induced a higher endurance performance on VO2 peak.