Lab #2: Metabolism and Energy Expenditure
1. The Respiratory exchange ratio is the ratio of the volume of carbon dioxide produced and oxygen consumed. The ratio indicates the energy that the subject is expending for indirect calorimetry, how efficient the subject 's body is at utilizing the oxygen inhaled, as well as the main substrate being used for energy during varying intensities of exercise. During rest the volume of carbon dioxide was 0.73L/min, the volume of oxygen was 0.84L/min. The RQ or RER was 0.87. Based on Table 5.1(Kenney,Wilmore, &Costill, 2012; Physiology of Sport and Exercise(5th ed.) The ratio indicates that roughly 68% of the kcal that the subject was using came from carbohydrates and the remaining 32% of the kcal came from fat. During the 50W stage the volume of carbon dioxide was 2.2L/min and the volume of oxygen was 2.9L/min. The RQ was 0.79, which indicates that the 33% of the kcal that the subject was using came from carbohydrates and that 67% of the kcal came from fat. In the 100W stage the volume of carbon dioxide was 4.08L/min and the volume of oxygen consumed was 4.1L/min. The RQ came out o be 0.99, the substrate being used was only carbohydrates at this point. The 200w stage had a carbon dioxide volume of 7.91L/min and a oxygen consumed volume of 6.51L/min. The RQ was 1.2 which indicates that the body is producing more carbon dioxide than the oxygen being consumed. The substrate being used for energy again is only carbohydrates.
2. Depending on the VO2 it will determine the amount of O2 being taken in by the lungs that is used by the muscles. An increase in O2 consumption indicates that more ATP is being produced so that the muscles can contract. Using the ratio of VCO2 and VO2 the RER can be obtained. Using the RER and the VO2 you can determine the main substrate being used and the amount ATP being produced based on the substrate being used, which can be used to calculate the kcal being used.
Bibliography: Kenny, W. L., Wilmore, J., & Costill , D. (2011). Physiology of sport and exercise . (5th ed., p.479). Human Kinetics.