Purpose: The purpose of this study was to evaluate the accuracy of the Polar M600 optical heart rate (OHR) sensor compared to ECG heart rate (HR) measurement during various physical activities.
Methods: Thirty-six subjects participated in a continuous 76 min testing session, which included rest, cycling warm up, cycling intervals, circuit weight training, treadmill intervals, and recovery. HR was measured using a 3-lead ECG configuration and a Polar M600 Sport Watch on the left wrist. Statistical analyses included OHR % accuracy, mean difference, mean absolute error, Bland-Altman plots, and a repeated measures Generalized Estimating Equation design. OHR % accuracy was calculated as the percentage of occurrences where OHR measurement was within and including +/- 5 bpm from the ECG HR value.
Results: Of the four exercise phases performed, the highest OHR % accuracy was found during cycle intervals (91.8%), and the lowest OHR % accuracy occurred during circuit weight training (34.5%). OHR % accuracy improved steadily within exercise transitions during cycle intervals to a maximum of 98.5%, and during treadmill intervals to a maximum of 89.0%. Lags in HR calculated by the Polar M600 OHR sensor existed in comparison to ECG HR, when exercise intensity changed until steady state occurred. There was tendency for OHR underestimation during intensity increases and overestimation during intensity decreases. No statistically significant interaction effect with device was found in this sample based on sex, BMI, V[spacing dot above]O2max, skin type, or wrist size.
Conclusions: The Polar M600 was accurate during periods of steady state cycling, walking, jogging, and running, but less accurate during some exercise intensity changes, which may be attributed to factors related to total peripheral resistance changes and pulse pressure.
(C) 2017 American College of Sports Medicine