Summary: The exercise stress test is a maximal exercise test used to calculate VO2 max. Mice are run to complete exhaustion as the treadmill speed is increased every three minutes (See table 1). During the test, direct measurements of the oxygen consumption and carbon dioxide output by the mouse are made, which are then used to calculate VO2 max, VCO2, and RER. VO2 max refers to the maximum amount of oxygen that the mouse can utilize during maximal exercise.