Shown and described is a method for controlling and/or regulating a spiroergometry system (1) for determining energy metabolism during physical exertion, wherein the spiroergometry system (1) has a user unit (2) arranged in the flow of the inhaled and exhaled air of a test subject (4) for removing a respiratory gas sample of the test subject (4), at least one analysis unit (5) for measuring the respiratory gas composition and/or the respiratory flow volume and for determining physiological parameters relating to the ventilation and/or gas exchange of the test subject (4), particularly for determining the oxygen volume taken in during at least one inhalation of the test subject (4) and the carbon dioxide volume exhaled after the breath and, preferably, the respiratory quotient, at least one measuring device (6) for measuring the heart rate of the test subject (4), at least one control device (7) for controlling the spiroergometry system (1) and a cardio equipment unit (8) for the physical exertion of the test subject (4), wherein as the exertion of the test subject increases incrementally during use of the cardio equipment unit (8), a measurement of the respiratory gas composition and/or respiratory flow volume is performed automatically only toward the end of an exertion stage or of a performance stage prior to an increase in exertion, and a determination is made of the physiological parameters, particularly a determination of the inhaled oxygen volume and of the exhaled carbon dioxide volume with respect to at least one breath toward the end of the exertion stage.
