Use of the Fitbit to Measure Adherence to a Physical Activity Intervention Among Overweight or Obese, Postmenopausal Women: Self-Monitoring Trajectory During 16 Weeks

Abstract

BackgroundDirect-to-consumer trackers and devices have potential to enhance theory-based physical activity interventions by offering a simple and pleasant way to help participants self-monitor their behavior. A secondary benefit of these devices is the opportunity for investigators to objectively track adherence to physical activity goals across weeks or even months, rather than relying on self-report or a small number of accelerometry wear periods. The use of consumer trackers for continuous monitoring of adherence has considerable potential to enhance physical activity research, but few studies have been published in this rapidly developing area.ObjectiveThe objective of the study was to assess the trajectory of physical activity adherence across a 16-week self-monitoring intervention, as measured by the Fitbit tracker.MethodsParticipants were 25 overweight or obese, postmenopausal women enrolled in the intervention arm of a randomized controlled physical activity intervention trial. Each participant received a 16-week technology-based intervention that used the Fitbit physical activity tracker and website. The overall study goal was 150 minutes/week of moderate to vigorous intensity physical activity (MVPA) and 10,000 steps/day; however, goals were set individually for each participant and updated at Week 4 based on progress. Adherence data were collected by the Fitbit and aggregated by Fitabase. Participants also wore an ActiGraph GT3X+ accelerometer for 7 days prior to the intervention and again during Week 16.ResultsThe median participant logged 10 hours or more/day of Fitbit wear on 95% of the 112 intervention days, with no significant decline in wear over the study period. Participants averaged 7540 (SD 2373) steps/day and 82 minutes/week (SD 43) of accumulated “fairly active” and “very active” minutes during the intervention. At Week 4, 80% (20/25) of women chose to maintain/increase their individual MVPA goal and 72% (18/25) of participants chose to maintain/increase their step goal. Physical activity levels were relatively stable after peaking at 3 weeks, with only small declines of 8% for steps (P=.06) and 14% for MVPA (P=.05) by 16 weeks.ConclusionsThese data indicate that a sophisticated, direct-to-consumer activity tracker encouraged high levels of self-monitoring that were sustained over 16 weeks. Further study is needed to determine how to motivate additional gains in physical activity and evaluate the long-term utility of the Fitbit tracker as part of a strategy for chronic disease prevention.Trial RegistrationClinicaltrials.gov NCT01837147; http://clinicaltrials.gov/ct2/show/NCT01837147 (Archived by WebCite at http://www.webcitation.org/6d0VeQpvB)

Future directions in physical activity intervention research: expanding our focus to sedentary behaviors, technology, and dissemination

“…For example, Cadmus-Bertram et al (2015) found that the median participant wore their Fitbit for 10 or more hours per day on 95 % of the intervention days (16 week intervention) and Xu et al (2015) showed similar (almost 100 %) rates for daily Fitbit wear over 28 consecutive days. In another study, Arigo (2015) found that participants increased their physical activity from baseline to 6 weeks after completing an online intervention that included wearable technology and social networking.…”

Can a Free Wearable Activity Tracker Change Behavior? The Impact of Trackers on Adults in a Physician-Led Wellness Group

“…One study examined the usability and usefulness of trackers as perceived by adults 50 years of age and older with chronic illnesses, and found that trackers helped increase physical activity self-awareness and goal setting [20]. Another study examined how overweight or obese postmenopausal women used trackers and found that, while physical activity levels initially rose, they plateaued after 3 weeks [21]. This study raised the question of how to motivate individuals to achieve further gains after initial success.…”

Smart devices and healthy aging

“…In 2015, 232 million wearable electronic devices were sold worldwide, and sales increased by 18.4% in 2016 [17]. With this increase in popularity, behavioral change interventions are becoming more evident [18][19][20][21][22]. However, with their increasing popularity, questions as to the validity, accuracy and reliability of these devices become increasingly more important.…”