Hats off to Professor SeonAe Yeo who recently received a $2,000 Clinical and Translational Science Award (CTSA) from NC TraCS for a project titled “Validation of ActiGraph and ActivPal in Assessing Sedentary and Light Activities with Obese Pregnant Women” that she is conducting with Assistant Professor Lee Stoner of UNC’s Department of Exercise and Sport Science.
A summary of the funded study follows:
Few studies report the benefits of light physical activity (LPA) in pregnant women, despite the reported benefits in a high-risk subgroup of women with preeclampsia. This study is important, because absence of such objective data makes it difficult for providers to make recommendations. Although most activity monitors accurately register moderate/vigorous activity, studies are hampered by the lack of a monitor that is accurate in the LPA/sedentary range, and is compatible with the physical characteristics of pregnancy. This study will assess two types of wearable monitors, ActiGraph and ActivPal, at three locations (waist, ankle, thigh) for accuracy in the LPA/sedentary range, and usability in obese pregnant women.
Sedentary behavior is associated with increased risk of mortality and cardiovascular disease. Behavioral interventions have commonly implemented moderate physical activity (PA) for pregnant women to help improve maternal and fetal outcomes. However, few studies have addressed the effect of LPA, an activity level likely more feasible for overweight/obese pregnant women, who comprise 56% of pregnant North Carolinians. The few interventions that objectively measured PAs have used ActiGraph, worn at waist with an elastic band for the best assessment. However, this location may negatively affect accuracy and compliance over the extended time required for data collection in late pregnancy, because of the growing abdomen. While ActiGraph is the “gold standard”, studies have demonstrated that the ActivPal is moreaccurate and consistent in the LPA/sedentary range. However, the accuracy and wearability ofActivPal has never been demonstrated in obese pregnant women – a group that woulduniquely benefit from a low-cost LPA routine like stretching exercise.
The accuracy for wearable monitors (WMs) in estimating energy expenditure duringLPA/sedentary activities is unclear with pregnant women in the latter half of pregnancy with unique physiological and physical characteristics. Thus, the goal of this study is to examine: 1) the accuracy of 2 WMs (ActiGraph and ActivPAL) in estimating the intensity of sedentary and light physical activity in obese pregnant women as compared with the criterion measure of oxygen uptake measured by indirect calorimetry (Oxycon Mobile); and 2) feasibility by asking participants about ease of comfort and practicality of each device worn.
Our previous randomized trial studied an exercise intervention in sedentary overweight/obese and high risk pregnant women. We found that, compared to walking (a moderate PA), to which pregnant women adhered poorly, 10 or more weeks of stretching exercise (a light PA) reduced the incidence of preeclampsia by lowering BP and enhancing antioxidant up-regulation and production. The proposed study is a component of such translational research, testing a simple, scalable non-pharmacologic intervention for pregnant women with obesity, which disproportionately burdens low-income and minority women, at a time when their choices for physical activities are few.
The results of this pilot study will determine whether ActivPAL or ActiGraph is a better option for measuring overall daily PA, most of which are likely light PA and sedentary. Assessment of overall daily PA as a covariate is an important part of the future study.