Ecological Momentary Intervention to Replace Sedentary Time With Physical Activity to Improve Executive Function in Midlife and Older Latino Adults: Pilot Randomized Controlled Trial
Authors: Bronas Ulf G , Marquez David X , Fritschi Cynthia , Petrarca Katherine , Kitsiou Spyros , Ajilore Olu , Tintle Nathan 
Published: June 2024

Background
Exercise interventions often improve moderate to vigorous physical activity, but simultaneously increase sedentary time due to a compensatory resting response. A higher level of sedentary time is associated with a lower level of executive function, while increased moderate to vigorous physical activity is associated with improved global cognition and working memory among Latino adults. Latino adults are the fastest-growing minority group in the United States and are at high risk for cognitive decline, spend more time sedentary compared to non-Hispanic populations, and engage in low levels of physical activity. Interventions that are culturally appropriate for Latino adults to replace sedentary time with physical activity are critically needed.

Objective
This study aims to develop and test the feasibility and acceptability of an ecological momentary intervention (EMI; delivered in real time) that is individually designed to replace sedentary time with physical activity in Latino adults.

Methods
This pilot study randomized 39 (n=26, 67% female; mean age 61, SD 5.8 years) community-dwelling, Spanish-speaking Latino adults (1:1 allocation) to either a 6-week EMI program designed to replace sitting time with physical activity (20/39, 51%) or physical activity guidelines education (19/39, 49%). The program was conducted on the web and in Spanish. The intervention was individualized based on individual interview responses. The intervention included the use of a Fitbit activity monitor, weekly didactic phone meetings, interactive tools (SMS text messages), and coach-delivered feedback. Feasibility and acceptability were assessed via study satisfaction (Likert scales), motivation (ecological momentary assessment), retention, and compliance. Sedentary time and physical activity were assessed via 7-day actigraphy. Cognitive performance was assessed via the trail making test part A and B (part B=executive function) and via the National Institutes of Health Toolbox remote cognitive assessment. Statistical analysis included a linear model on change score from baseline, adjusting for age, sex, and education, emphasizing effect size.

Results
Participant satisfaction with EMI was high (9.4/10), with a high degree of motivation to replace sitting time with physical activity (9.8/10). The intervention compliance rate was 79% with low difficulty using the Fitbit (1.7/10). Weekly step count increased in the intervention group by 5543 steps (group difference: d=0.54; P=.05) and sedentary time decreased by a mean 348 (SD 485) minutes (group difference: d=0.47; P=.24) compared to controls, with moderately strong effect sizes. The trail making test part B improved in the intervention group (mean –35.26, SD 60.35 seconds), compared to the control group (mean 7.19, SD 46 seconds; group difference: d=0.74; P=.01). No group differences were observed in other cognitive measures.

Conclusions
An individualized EMI designed for midlife and older Latino adults has the potential to replace sitting time with physical activity and improve executive functioning. The intervention was feasible and well received with a high degree of satisfaction.

Trial Registration
ClinicalTrials.gov NCT04507464; https://tinyurl.com/44c4thk5