Department of Health, Kinesiology, and Recreation, University of Utah, Salt Lake City, UT, United States of America.
Department of Rehabilitation and Movement Science, University of Vermont, Burlington, VT, United States of America.
PLoS One. 2021 May 26;16(5):e0251975. doi: 10.1371/journal.pone.0251975. eCollection 2021.
The aim of this study was to evaluate the accuracy of three consumer-based activity monitors, Fitbit Charge 2, Fitbit Alta, and the Apple Watch 2, all worn on the wrist, in estimating step counts, moderate-to-vigorous minutes (MVPA), and heart rate in a free-living setting.
Forty-eight participants (31 females, 17 males; ages 18-59) were asked to wear the three consumer-based monitors mentioned above on the wrist, concurrently with a Yamax pedometer as the criterion for step count, an ActiGraph GT3X+ (ActiGraph) for MVPA, and a Polar H7 chest strap for heart rate. Participants wore the monitors for a 24-hour free-living condition without changing their usual active routine. MVPA was calculated in bouts of ≥10 minutes. Pearson correlation, mean absolute percent error (MAPE), and equivalence testing were used to evaluate the measurement agreement.
The average step counts recorded for each device were as follows: 11,734 (Charge2), 11,922 (Alta), 11,550 (Apple2), and 10,906 (Yamax). The correlations in steps for the above monitors ranged from 0.84 to 0.95 and MAPE ranged from 17.1% to 35.5%. For MVPA minutes, the average were 76.3 (Charge2), 63.3 (Alta), 49.5 (Apple2), and 47.8 (ActiGraph) minutes accumulated in bouts of 10 or greater minutes. The correlation from MVPA estimation for above monitors were 0.77, 0.91, and 0.66. MAPE from MVPA estimation ranged from 44.7% to 55.4% compared to ActiGraph. For heart rate, correlation for Charge2 and Apple2 was higher for sedentary behavior and lower for MVPA. The MAPE ranged from 4% to 16%.
All three consumer monitors estimated step counts fairly accurately, and both the Charge2 and Apple2 reported reasonable heart rate estimation. However, all monitors substantially underestimated MVPA in free-living settings.
本研究旨在评估三款腕戴式消费级活动监测器（Fitbit Charge 2、Fitbit Alta 和 Apple Watch 2）在自由活动环境下计步、中高强度活动时间（MVPA）和心率测量的准确性。
48 名参与者（31 名女性，17 名男性；年龄 18-59 岁）被要求同时佩戴上述三种腕戴式消费级监测器，同时使用 Yamax 计步器作为计步的标准，ActiGraph GT3X+（ActiGraph）作为 MVPA 的标准，以及 Polar H7 胸带作为心率的标准。参与者在 24 小时的自由生活条件下佩戴监测器，不改变其日常活动习惯。MVPA 计算为持续 10 分钟或更长时间的活动。采用皮尔逊相关系数、平均绝对百分比误差（MAPE）和等效性检验来评估测量一致性。
每个设备记录的平均步数分别为：11734（Charge2）、11922（Alta）、11550（Apple2）和 10906（Yamax）。上述监测器的步幅相关系数范围为 0.84 至 0.95，MAPE 范围为 17.1%至 35.5%。对于 MVPA 分钟数，平均分别为 76.3（Charge2）、63.3（Alta）、49.5（Apple2）和 47.8（ActiGraph）分钟，这些分钟数是在持续 10 分钟或更长时间的活动中累计的。上述监测器的 MVPA 估计相关系数为 0.77、0.91 和 0.66。与 ActiGraph 相比，MVPA 估计的 MAPE 范围为 44.7%至 55.4%。对于心率，Charge2 和 Apple2 的静息行为相关性较高，MVPA 相关性较低。MAPE 范围为 4%至 16%。
所有三款消费级监测器在计步方面都相当准确，Charge2 和 Apple2 两款监测器报告的心率测量也比较合理。然而，所有监测器在自由活动环境下都大大低估了 MVPA。
