JMIR Publications

ABSTRACT

Background:

Physical activity (PA) plays a fundamental role in combatting the current obesity epidemic, yet women who are overweight or obese are generally physically inactive. Wearable activity tracker interventions can help to increase PA levels in this population. Supplementing such interventions with behavioral support emails may further improve their effectiveness, but it remains to be confirmed.

Objective:

To determine if adding behavioral support emails to a wearable activity tracker intervention can further increase PA levels among women who are overweight and obese in comparison to a wearable activity tracker only intervention and a control condition.

Methods:

Women with a body mass index (BMI) ≥25kg/m2 who did not meet the Canadian PA guidelines for aerobic and strength training were randomized into one of three groups. Group 1 received (A) six weekly behavioral support emails, (B) a wearable activity tracker, and (C) a copy of the Canadian PA guidelines. Group 2 received (B) and (C) and Group 3 (control condition) received (C). Self-reported data for walking and moderate-to-vigorous intensity PA (MVPA) were collected pre-intervention (week 0; pre-randomization), post-intervention (7 weeks post-randomization), and at follow-up (21 weeks post-randomization) and analyzed as metabolic equivalent of task (MET)-minutes per week. Additionally, potential mechanisms of behavior change (i.e., basic psychological needs satisfaction and motivational regulations) were assessed for within- and between-group differences at all three timepoints. Data were analyzed using non-parametric statistical tests.

Results:

A total of 49 women were recruited; data from 47 women (Mage=37.5711.78 years, MBMI=31.695.97 kg/m2) were available for analysis. Group 1 reported a significant increase in walking from pre- to post-intervention [2(2)=7.53, P=.02], but not in MVPA (P>.05). Group 1 also reported significant increases in perceptions of competence from pre-intervention to follow-up [2(2)=7.56, P=.02], and relatedness from pre-intervention to follow-up [2(2)=8.67, P=.005]. Increases in perceived autonomy were observed for Group 2 [2(2)=6.98] and Group 3 [2(2)=10.57]. There were no significant changes in motivational regulations within groups. The difference between groups was not significant for any outcome variable.

Conclusions:

Results suggest that adding behavioral support emails to a wearable activity tracker intervention may help to increase time spent walking and perceptions of competence and relatedness for PA among women who are overweight or obese. Clinical Trial: This trial was registered at ClinicalTrials.gov (ID: NCT03601663, Date: July 26, 2018; http://clinicaltrials.gov/ct2/show/NCT03601663).