E-33 Free Communication/Poster - Monitoring Friday, June 2, 2017, 7:30 AM - 12:30 PM Room: Hall F
Physical activity tracking wearables have emerged as a popular method for consumers to assess their daily activity, calories expended and heart rate. However, less is known if these health measures are valid at various levels of exercise intensity.
PURPOSE: To examine heart rate (HR) and energy expenditure (EE) validity of three popular wrist-worn activity monitors at different exercise intensities.
METHODS: 62 participants (36 females, 46.8% non-white) wore the Apple Watch (AW), Fitbit Charge HR (FCHR) and Garmin Forerunner 225 (GF). Validity was assessed by 2 criterion devices: HR chest strap and a metabolic cart. Participants completed a 10-min seated baseline; separate 4-min stages of light, moderate and vigorous-intensity treadmill exercises; and a 10-min seated recovery. Data from devices were compared to each criterion via two-way RM-ANOVA and Bland-Altman analysis. Differences were expressed in mean absolute percentage error values (MAPE).
RESULTS: AW - HR MAPE between 1.14-6.70%. HR not significantly different at the start (p = .13), baseline (p = .76) or vigorous intensity (p = .84). Lower HR readings during light (p < .05), moderate (p < .01) and recovery (p < .01). EE MAPE between 14.07-210.84%. Measured higher EE at all stages (p < .01). FCHR - HR MAPE between 2.38-16.99%. HR not significantly different at start (p = .43) or moderate intensity (p = .34). Lower HR readings during baseline, vigorous and recovery (p < .001) and higher HR in light (p < .001). EE MAPE between 16.85-84.98%. Measured higher EE at baseline (p < .05), light (p < .001) and moderate (p < .001). GF - HR MAPE between 7.87-24.38%. HR not significantly different at vigorous intensity (p = .35). Measured higher HR readings start, baseline, light, moderate (p < .001) and recovery (p < .05). EE MAPE between 30.77-155.05%. Measured higher EE at all stages (p < .001).
CONCLUSION: This study provides one of the first validation assessments for the Fitbit Charge HR, Apple Watch and Garmin Forerunner 225. An advantage and novel approach of the study is the examination of HR and EE at specific PA intensities. Establishing validity of wearables is of particular interest as these devices are being used in weight loss interventions and could impact findings. Future research should investigate why differences between exercise intensities and the devices exist.