The invention relates to a method for controlling a training device, comprising the following steps: providing a defined room atmosphere in a training room (28), in which a training device (2) is located； determining a respiratory quotient of a test subject (3) using the training device (2) in the training room (28)； and using the respiratory quotient of the test subject (3) as an input variable for controlling the training device (2). The method is characterized in that the room atmosphere in the training room (28) has a constant oxygen content, which is in the range of 22 to 32 volume percent, and that a specifiable power equivalent of the training device (2) in a range of 50 to 80 watts is varied according to the respiratory quotient of the test subject (3) in such a way that the respiratory quotient of the test subject (3) assumes a value in a range of 0.77 to 0.85. The invention further relates to a device for providing a defined room atmosphere having an oxygen content of 22 to 32 volume percent in a training room (28).
