1. Comparing Methods to Identify Wear-Time Intervals for Physical Activity With the Fitbit Charge 2.
- Author
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Claudel, Sophie E., Tamura, Kosuke, Troendle, James, Andrews, Marcus R., Ceasar, Joniqua N., Mitchell, Valerie M., Vijayakumar, Nithya, and Powell-Wiley, Tiffany M.
- Subjects
PHYSICAL fitness mobile apps ,BLACK people ,WEARABLE technology ,PHYSICAL activity ,HEART beat ,DESCRIPTIVE statistics ,STATISTICAL sampling ,ALGORITHMS - Abstract
There is no established method for processing data from commercially available physical activity trackers. This study aims to develop a standardized approach to defining valid wear time for use in future interventions and analyses. Sixteen African American women (mean age = 62.1 years and mean body mass index = 35.5 kg/m
2 ) wore the Fitbit Charge 2 for 20 days. Method 1 defined a valid day as ≥10-hr wear time with heart rate data. Method 2 removed minutes without heart rate data, minutes with heart rate ≤ mean − 2 SDs below mean and ≤2 steps, and nighttime. Linear regression modeled steps per day per week change. Using Method 1 (n = 292 person-days), participants had 20.5 (SD = 4.3) hr wear time per day compared with 16.3 (SD = 2.2) hr using Method 2 (n = 282) (p <.0001). With Method 1, participants took 7,436 (SD = 3,543) steps per day compared with 7,298 (SD = 3,501) steps per day with Method 2 (p =.64). The proposed algorithm represents a novel approach to standardizing data generated by physical activity trackers. Future studies are needed to improve the accuracy of physical activity data sets. [ABSTRACT FROM AUTHOR]- Published
- 2021
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