Garrett J. Janicki1, John P. Porcari1, Andrew R. Jagim1-2, Kari Emineth1, Scott Dorberstein1, Elizabeth Schwab1, Carol Foster1. The Accuracy of Heart Rate and Energy Expenditure Measurements using the PolarM430 Watch during Exercise. 1Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI, USA; 2Sports Medicine, Mayo Clinic Health System, La Crosse, WI, USA.
Purpose: The aim of the current study was to assess the accuracy of the Polar M430 fitness watch for the measurement of heart rate (HR) and energy expenditure (EE) during low, moderate, and high intensity treadmill exercise. Methods: Twenty subjects (males, n = 12; Age: 24.2 ± 2.41 yrs., Height: 175.7 ± 6.85 cm, Weight: 88.1 ± 13.02 kg; BMI: 28.44 ± 2.90 kg/m2) (females, n = 8; Age: 22.5 ± 2.98 yrs., Height: 171.9 ± 4.48 cm, Weight: 73.3 ± 9.10 kg; BMI: 24.81 ± 3.00 kg/m2) completed a single bout of exercise on a treadmill at three incremental intensities using self-selected ratings of perceived exertion (RPE) – derived workloads at RPE 11 (low intensity), RPE 13 (moderate intensity), and RPE 15 (high intensity), respectively. Each workload was 5-minutes in duration and subjects wore a PolarM430 watch throughout the entire protocol. An electrocardiogram (ECG) and indirect calorimetry were used as criterion measures of HR and EE, respectively. Two-way ANOVA with repeated measures was used to examine differences in HR and EE between the PolarM430 and criterion measures. Pairwise comparisons were made using Tukey’s post-hoc tests. Intraclass correlation coefficients were used to examine the relationship between HR and EE. Data are presented as mean ± 95% confidence intervals. Results: The PolarM430 significantly underestimated HR at RPE 15 -3.20 (-5.00, -1.40) bpm. ICC analysis indicated an excellent level of agreement between the PolarM430 and criterion measures for HR (ICC =.96-.99). The PolarM430 significantly underestimated EE by -19.25 (-14.77, -3.37) kcals (14.9%) at RPE 15 and -10.5 (-20.09, -0.91) kcals (-8.78%) throughout the entire testing protocol. ICC analysis indicated a moderate to good level of agreement (ICC = .66-.89) for EE. Conclusions: Based on these results, it appears the Polar M430 fitness watch is an accurate tool to measure HR at low to moderate exercise intensities, but may underestimate HR at higher exercise intensities. The PolarM430 watch appears to be an accurate tool to measure EE during low and moderate intensity exercise, but may underestimate EE at higher exercise intensities, as well as over the course of an entire bout of exercise.