Inter-instrument reliability and agreement of fitbit charge measurements of heart rate and activity at rest, during the modified Canadian aerobic fitness test, and in recovery

© 2019, University of Toronto Press Inc.. All rights reserved. Purpose: We determined the inter-instrument reliability and agreement parameters of the Fitbit Charge Heart Rate (Charge HR) device during three phases: rest, modified Canadian Aerobic Fitness Test (mCAFT), and recovery. Method: We recruited 60 participants for this cross-sectional measurement study using convenience and snowball sampling approaches. The performance of the Charge HR was assessed throughout the rest, mCAFT, and recovery phases. To establish inter-instrument reliability, the Charge HR variables – heart rate, steps taken, and energy expenditures – were compared with those for two other devices: the Zephyr BioHarness (ZB) for heart rate and the Fitbit One for steps taken and energy expenditure. Measurements were recorded every 30 seconds. Results: At rest, the inter-instrument intra-class correlation coefficient (ICC) (standard error of measurement [SEM]) for the Charge HR versus the ZB was \u3e 0.97 (range, min–max, 1.02–1.32). During the mCAFT and in recovery, the ICCs (SEMs) for the Charge HR and the ZB were \u3e 0.89 (range, min–max, 1.30–3.98) and \u3e 0.68 (range, min–max, 3.58–8.35), respectively. During the mCAFT only, the number of steps taken and the energy expenditure recorded by the Charge HR and the Fitbit One displayed ICCs (SEMs) of 0.97 (83.00) and 0.77 (14.70), respectively. The average agreement differences in heart rate in this pair-wise device comparison indicated mean differences of –0.20, 4.00, and 1.00 beats per minute at rest, during the mCAFT, and in recovery, respectively. Conclusions: The Charge HR heart rate variable demonstrated excellent inter-instrument reliability compared with the ZB and provided good levels of agreement. The steps taken and energy expenditure variables displayed excellent reliability measures between Charge HR and Fitbit One. Our findings may be used to capture field-based wireless measures of heart rate in various phases and provide information about possibly using the Charge HR and ZB devices interchangeably

Comparison of Non-Invasive Individual Monitoring of the Training and Health of Athletes with Commercially Available Wearable Technologies

Athletes adapt their training daily to optimize performance, as well as avoid fatigue, overtraining and other undesirable effects on their health. To optimize training load, each athlete must take his/her own personal objective and subjective characteristics into consideration and an increasing number of wearable technologies (wearables) provide convenient monitoring of various parameters. Accordingly, it is important to help athletes decide which parameters are of primary interest and which wearables can monitor these parameters most effectively. Here, we discuss the wearable technologies available for non-invasive monitoring of various parameters concerning an athlete's training and health. On the basis of these considerations, we suggest directions for future development. Furthermore, we propose that a combination of several wearables is most effective for accessing all relevant parameters, disturbing the athlete as little as possible, and optimizing performance and promoting health