Measurement of exercise ventilation by a portable respiratory inductive plethysmograph.

The purpose of this study was to evaluate the accuracy of a respiratory inductive plethysmograph (RIP) designed for ambulatory data collection during exercise by comparison to a pneumotachograph. Healthy young males (n=10) wore an elastic body garment embedded with inductance sensors encircling the rib cage and abdomen. Breathing frequency (f(R)), tidal volume (V(T)) and minute ventilation (V (I)) were monitored during 5min of rest, slow walking (3.7kmh(-1)), fast walking (6.1kmh(-1)) and slow running (8.9kmh(-1)) followed by an incremental treadmill test to exhaustion (14.4+/-2.7kmh(-1)). Mean f(R), V(T) and V (I) values were not statistically different between the two methods (P>0.05). Within each of the subjects at rest and different exercise intensities, the average coefficient of determination was high for f(R), V(T) and V (I) (R(2)=0.9233, 0.8743 and 0.9652, respectively) and the mean bias values were low (-0.102+/-2.91, 0.033+/-0.207 and -0.715+/-8.362, respectively). These data suggest that the ambulatory RIP provides reasonable estimates of ventilation during rest and exercise.