Target device for regulating ventilation during voluntary hyperpnea

target device is described enabling subjects to maintain speci-fied levels of ventilation during voluntary hyperpnea. Inspired air passes through a linear resistor. The associated pressure drop is measured and displayed by a mechanical manometer with a very slow response. This time-mean pressure is propor-tional to time-mean inspiratory flow and thus to inspired minute ventilation. Construction and calibration are described. Inspiratory resistances range between 0.6 and 1.9 cmHzOo 1-l s for devices with capacities up to 240 and 80 l/min, respectively. The device is simple, cheap, stable, portable, rugged, unpow-ered, and accurate. Inexperienced subjects quickly learn to use it and can maintain ventilations within about 5 % of specified values. fatigue; respiratory muscles; respiration; respiratory mechanics I NEEDED a quantitative ventilatory target to guide sub