Accuracy of the Ohmeda 3700 Pulse Oximeter in Estimating Heart Rate during Exercise

Pulse oximeters are often used as a means of estimating heart rate (HR) at rest and during exercise. However, at present, few data have been reported to support the validity of this practice. METHOD: We evaluated the accuracy of a pulse oximeter (Ohmeda 3700), utilizing an ear sensor to estimate HR during incremental exercise, by comparing the oximeter estimates of HR to simultaneous electrocardiograph (ECG) HR measurements. Data were collected on 26 subjects (284 HR measurements) during graded cycle-ergometer exercise to volitional fatigue. RESULTS: Analysis by linear regression revealed r = 0.91 (SEE = ±14.4) for HR over the entire range of exercise HR measurements. Mean HRs determined from the ECG recording and the ear-oximeter estimate at selected work rates were not significantly different (p = 0.68) for HR below 160 beats/min. However, the pulse oximeter significantly underestimated HR ⩾ 160 beats/min (p<0.0001). CONCLUSION: We conclude that the Ohmeda 3700 pulse oximeter provides accurate estimates of HR during cycle-ergometer exercise when HR is < 160 beats/min, but may provide inaccurate estimates when true HR is ⩾ 160 beats/min.