@Article{info:doi/10.2196/mhealth.8503,
author="Hartman, Sheri J
and Nelson, Sandahl H
and Weiner, Lauren S",
title="Patterns of Fitbit Use and Activity Levels Throughout a Physical Activity Intervention: Exploratory Analysis from a Randomized Controlled Trial",
journal="JMIR Mhealth Uhealth",
year="2018",
month="Feb",
day="05",
volume="6",
number="2",
pages="e29",
keywords="physical activity; technology; activity tracker; self-monitoring; adherence",
abstract="Background: There has been a rapid increase in the use of technology-based activity trackers to promote behavior change. However, little is known about how individuals use these trackers on a day-to-day basis or how tracker use relates to increasing physical activity. Objective: The aims were to use minute level data collected from a Fitbit tracker throughout a physical activity intervention to examine patterns of Fitbit use and activity and their relationships with success in the intervention based on ActiGraph-measured moderate to vigorous physical activity (MVPA). Methods: Participants included 42 female breast cancer survivors randomized to the physical activity intervention arm of a 12-week randomized controlled trial. The Fitbit One was worn daily throughout the 12-week intervention. ActiGraph GT3X+ accelerometer was worn for 7 days at baseline (prerandomization) and end of intervention (week 12). Self-reported frequency of looking at activity data on the Fitbit tracker and app or website was collected at week 12. Results: Adherence to wearing the Fitbit was high and stable, with a mean of 88.13{\%} of valid days over 12 weeks (SD 14.49{\%}). Greater adherence to wearing the Fitbit was associated with greater increases in ActiGraph-measured MVPA (binteraction=0.35, P<.001). Participants averaged 182.6 minutes/week (SD 143.9) of MVPA on the Fitbit, with significant variation in MVPA over the 12 weeks (F=1.91, P=.04). The majority (68{\%}, 27/40) of participants reported looking at their tracker or looking at the Fitbit app or website once a day or more. Changes in Actigraph-measured MVPA were associated with frequency of looking at one's data on the tracker (b=−1.36, P=.07) but not significantly associated with frequency of looking at one's data on the app or website (P=.36). Conclusions: This is one of the first studies to explore the relationship between use of a commercially available activity tracker and success in a physical activity intervention. A deeper understanding of how individuals engage with technology-based trackers may enable us to more effectively use these types of trackers to promote behavior change. Trial Registration: ClinicalTrials.gov NCT02332876; https://clinicaltrials.gov/ct2/show/NCT02332876?term=NCT02332876 {\&}rank=1 (Archived by WebCite at http://www.webcitation.org/6wplEeg8i). ",
issn="2291-5222",
doi="10.2196/mhealth.8503",
url="https://mhealth.jmir.org/2018/2/e29/",
url="https://doi.org/10.2196/mhealth.8503",
url="http://www.ncbi.nlm.nih.gov/pubmed/29402761"
}