Abstract: A mobile ergospirometry system including a portable measurement unit that can be attached to a subject and that incorporates a mouthpiece or mask to collect respiratory gas, a sensor for the volume or amount of gas as well as sensors to determine the CO2/O2 concentration in the respiratory gas, a signal processing unit, and a telemetry module. The system further includes a computer-assisted base station having a telemetry unit to create a wireless connection to the telemetry module. In the system a bidirectional transmission route to the telemetry unit is set up by the telemetry module to transmit data and commands, for which purpose a transmitter and receiver subassembly is provided in each case, so that from the base station it is possible to communicate to the subject online information or requirements for operation of the measurement unit and/or the progress of the test.