Using a consumer-based wearable activity tracker for physical activity goal setting and measuring steps in pregnant women with gestational diabetes mellitus: exploring acceptance and validity

Samantha F Ehrlich,Jill M Maples,Nikki B Zite,Cristina S Barroso,David R Bassett,Kimberly B Fortner,Kathleen C Brown

doi:10.1186/s12884-021-03900-8

Samantha F Ehrlich, Jill M Maples + Show 5 more

Open Access

https://doi.org/10.1186/s12884-021-03900-8

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Abstract

BackgroundActivity monitoring devices may be used to facilitate goal-setting, self-monitoring, and feedback towards a step-based physical activity (PA) goal. This study examined the performance of the wrist-worn Fitbit Charge 3™ (FC3) and sought opinions on walking and stepping-in-place from women with gestational diabetes (GDM).MethodsParticipants completed six 2-min metronome-assisted over ground bouts that varied by cadence (67, 84, or 100 steps per minute) and mode (walking or stepping-in-place; N = 15), with the sequence randomized. Steps were estimated by FC3 and measured, in duplicate, by direct observation (hand-tally device, criterion). Equivalence testing by the two one-sided tests (TOST) method assessed agreement within ± 15%. Mean absolute percent error (MAPE) of steps were compared to 10%, the accuracy standard of the Consumer Technology Association (CTA)™. A subset (n = 10) completed a timed, 200-m self-paced walk to assess natural walking pace and cadence. All participants completed semi-structured interviews, which were transcribed and analyzed using descriptive and interpretive coding.ResultsMean age was 27.0 years (SD 4.2), prepregnancy BMI 29.4 kg/m2 (8.3), and gestational age 32.8 weeks (SD 2.6). The FC3 was equivalent to hand-tally for bouts of metronome-assisted walking and stepping-in-place at 84 and 100 steps per minute (i.e., P < .05), although walking at 100 steps per minute (P = .01) was no longer equivalent upon adjustment for multiple comparisons (i.e., at P < .007). The FC3 was equivalent to hand-tally during the 200-m walk (i.e., P < .001), in which mean pace was 68.2 m per minute (SD 10.7), or 2.5 miles per hour, and mean cadence 108.5 steps per minute (SD 6.5). For walking at 84 and 100 steps per minute, stepping-in-place at 100 steps per minute, and the 200-m walk, MAPE was within 10%, the accuracy standard of the CTA™. Interviews revealed motivation for PA, that stepping-in-place was an acceptable alternative to walking, and competing responsibilities made it difficult to find time for PA.ConclusionsThe FC3 appears to be a valid step counter during the third trimester, particularly when walking or stepping-in-place at or close to women’s preferred cadence.

Highlights

Activity monitoring devices may be used to facilitate goal-setting, self-monitoring, and feedback towards a step-based physical activity (PA) goal
The Standards provide guidance on medical nutrition therapy and weight management [i.e., weight gain according to the 2009 Institute of Medicine recommendations [4], which are specific to women’s prepregnancy body mass index (BMI) category, recommending 12.5–18 kg, 11.5–16 kg, 7–11.5 kg, and 5–9 kg for underweight women, healthy weight women, women with overweight and women with obesity, respectively], but offer no further advice pertaining to PA [3]
The American College of Obstetricians and Gynecologists (ACOG) suggests that women who were physically active before pregnancy or habitually participate in vigorous-intensity activity continue these activities during pregnancy [5]

Summary

Introduction

Activity monitoring devices may be used to facilitate goal-setting, self-monitoring, and feedback towards a step-based physical activity (PA) goal. The American Diabetes Association’s Standards of Medical Care in Diabetes (Standards) recommend that after a GDM diagnosis, treatment begin with medical nutrition therapy, PA, and, depending on pregestational weight class, weight management [3]. The American College of Obstetricians and Gynecologists (ACOG) suggests that women who were physically active before pregnancy or habitually participate in vigorous-intensity activity continue these activities during pregnancy [5]. ACOG recommends 150 min per week of moderate-intensity aerobic exercise, and that walking for 10–15 min after each meal can improve glycemic control [5]. Randomized controlled trials of exercise interventions in women with GDM clearly demonstrate improvements in glucose [5, 6], behavioral PA interventions that are appropriate for the clinical setting are largely lacking [7]

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