A number of exercise instruments, schemes, and protocols for evaluating the dyspneic patient are characterized. The cycle is safe, allows quantification of external work and work efficiency, and has less measurement artifact, whereas the treadmill allows a higher maximum oxygen uptake. Repeated measures of cardiorespiratory function at rest, during several minutes of warmup, and during work, with equal 1-min increments, to a symptom-limited maximum in approximately 10 min is an advantageous protocol.