Comparison of heart rate measured by Polar RS 400 and ECG, validity and repeatability

Aims: The purpose of this study was to investigate criterion-related validity and test–retest repeatability of the heart rate monitor Polar RS400 versus electrocardiogram (ECG). Methodology: Ten healthy subjects, 19–34 years, performed a cycle ergometer test 5 min on each load (50, 100 and 150 W). Heart rate (HR) was measured with ECG and Polar RS400 and recorded digitally. After at least one hour resting the test was repeated. Major findings: The results showed a significant correlation between HR measured by ECG and by Polar RS400 with correlation coefficients ranging from 0.97 to 1.00. In test 1 the mean difference ± 2SD between HR Polar and HR ECG was 0.7 ± 4.3 bpm and in test 2, 0.2 ± 3.2 bpm. In the repeated tests, the mean difference of HR between test 2 and test 1 ± 2SD was 3.2 ± 11.9 bpm with ECG and 2.6 ± 14.3 bpm with Polar RS400 and these differences were not statistically significant. Conclusion: This study indicates good criterion-related validity and test–retest repeatability of Polar RS400. Differences observed at individual levels should be noticed, but are not considered to be clinically important. Polar RS400 is thus well suited for recording HR during physical activity and exercise training.