Dooley Erin E, Golaszewski Natalie M, Bartholomew John B
Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, United States.
JMIR Mhealth Uhealth. 2017 Mar 16;5(3):e34. doi: 10.2196/mhealth.7043.
Physical activity tracking wearable devices have emerged as an increasingly popular method for consumers to assess their daily activity and calories expended. However, whether these wearable devices are valid at different levels of exercise intensity is unknown.
The objective of this study was to examine heart rate (HR) and energy expenditure (EE) validity of 3 popular wrist-worn activity monitors at different exercise intensities.
A total of 62 participants (females: 58%, 36/62; nonwhite: 47% [13/62 Hispanic, 8/62 Asian, 7/62 black/ African American, 1/62 other]) wore the Apple Watch, Fitbit Charge HR, and Garmin Forerunner 225. Validity was assessed using 2 criterion devices: HR chest strap and a metabolic cart. Participants completed a 10-minute seated baseline assessment; separate 4-minute stages of light-, moderate-, and vigorous-intensity treadmill exercises; and a 10-minute seated recovery period. Data from devices were compared with each criterion via two-way repeated-measures analysis of variance and Bland-Altman analysis. Differences are expressed in mean absolute percentage error (MAPE).
For the Apple Watch, HR MAPE was between 1.14% and 6.70%. HR was not significantly different at the start (P=.78), during baseline (P=.76), or vigorous intensity (P=.84); lower HR readings were measured during light intensity (P=.03), moderate intensity (P=.001), and recovery (P=.004). EE MAPE was between 14.07% and 210.84%. The device measured higher EE at all stages (P<.01). For the Fitbit device, the HR MAPE was between 2.38% and 16.99%. HR was not significantly different at the start (P=.67) or during moderate intensity (P=.34); lower HR readings were measured during baseline, vigorous intensity, and recovery (P<.001) and higher HR during light intensity (P<.001). EE MAPE was between 16.85% and 84.98%. The device measured higher EE at baseline (P=.003), light intensity (P<.001), and moderate intensity (P=.001). EE was not significantly different at vigorous (P=.70) or recovery (P=.10). For Garmin Forerunner 225, HR MAPE was between 7.87% and 24.38%. HR was not significantly different at vigorous intensity (P=.35). The device measured higher HR readings at start, baseline, light intensity, moderate intensity (P<.001), and recovery (P=.04). EE MAPE was between 30.77% and 155.05%. The device measured higher EE at all stages (P<.001).
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 physical activity intensities. Establishing validity of wearable devices 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.
身体活动追踪可穿戴设备已成为消费者评估日常活动和消耗卡路里的一种越来越流行的方法。然而，这些可穿戴设备在不同运动强度水平下是否有效尚不清楚。
本研究的目的是检验3种流行的腕戴式活动监测器在不同运动强度下的心率（HR）和能量消耗（EE）有效性。
共有62名参与者（女性：58%，36/62；非白人：47%[13/62西班牙裔、8/62亚裔、7/62黑人/非裔美国人、1/62其他]）佩戴了苹果手表、Fitbit Charge HR和佳明Forerunner 225。使用两种标准设备评估有效性：心率胸带和代谢车。参与者完成了10分钟的坐姿基线评估；分别进行4分钟的轻度、中度和剧烈强度跑步机运动阶段；以及10分钟的坐姿恢复期。通过双向重复测量方差分析和布兰德-奥特曼分析将设备数据与每个标准进行比较。差异以平均绝对百分比误差（MAPE）表示。
对于苹果手表，心率MAPE在1.14%至6.70%之间。心率在开始时（P =.78）、基线期间（P =.76）或剧烈强度时（P =.84）无显著差异；在轻度强度（P =.03）、中度强度（P =.001）和恢复期（P =.004）测量到较低的心率读数。能量消耗MAPE在14.07%至210.84%之间。该设备在所有阶段测量到的能量消耗较高（P <.01）。对于Fitbit设备，心率MAPE在2.38%至16.99%之间。心率在开始时（P =.67）或中度强度时（P =.34）无显著差异；在基线、剧烈强度和恢复期测量到较低的心率读数（P <.001），在轻度强度时测量到较高的心率（P <.001）。能量消耗MAPE在16.85%至84.98%之间。该设备在基线（P =.003）、轻度强度（P <.001）和中度强度（P =.001）时测量到较高的能量消耗。在剧烈强度（P =.70）或恢复期（P =.10）时能量消耗无显著差异。对于佳明Forerunner 225，心率MAPE在7.87%至24.38%之间。心率在剧烈强度时（P =.35）无显著差异。该设备在开始、基线、轻度强度、中度强度（P <.001）和恢复期（P =.04）测量到较高的心率读数。能量消耗MAPE在30.77%至155.05%之间。该设备在所有阶段测量到的能量消耗较高（P <.001）。
本研究为Fitbit Charge HR、苹果手表和佳明Forerunner 225提供了首批验证评估之一。该研究的一个优势和新颖方法是在特定身体活动强度下检查心率和能量消耗。确定可穿戴设备的有效性特别重要，因为这些设备正用于减肥干预措施中，可能会影响研究结果。未来的研究应调查运动强度与设备之间存在差异的原因。
