Exploring the Acute Effects of Sedentary Behaviors on Cardiometabolic Risk in Hispanic Adolescents with Obesity: A Randomized Crossover Study

<b>Background/Objectives</b>: Time spent in sedentary pursuits is associated with adverse metabolic profiles. Adolescents spend 65-75% of their day in sedentary pursuits; however, evidence among youth is less conclusive. This study examined the effects of an acute 4 h bout of sedentary behaviors on cardiometabolic outcomes and energy expenditure in Hispanic adolescents (12-16 years old) with obesity (BMI% ≥ 95th). <b>Methods</b>: This study used a randomized cross-over design to engage participants (N = 12) in two sedentary conditions, an active condition where youth were engaged in two hours of 'active' sitting activities (e.g., reading and puzzles) and two hours of passive movie-watching. Whole-room calorimetry was used to assess energy expenditure. Fasting measures of insulin, adiponectin, leptin, and TNF-alpha were collected, followed by post-prandial measures 30 min, 2 h, and 4 h after a standardized meal. Adiposity was assessed using DXA. <b>Results</b>: There was no overall impact of the 4 h sedentary bout on energy expenditure or cardiometabolic risk factors; however, energy expenditure in the active sedentary condition was higher compared to the passive sedentary condition (<i>p</i> = 0.0635, ß estimate = 0.1538). Sex and adiposity did not moderate the relationships among sedentary time, cardiometabolic outcomes, and energy expenditure. <b>Conclusions</b>: Due to power limitations, these results are exploratory; however, they suggest that different types of sedentary behaviors may be more deleterious than others. More studies are needed to understand the context in which sedentary activities occur and the mechanisms by which sedentary pursuits contribute to the development of cardiometabolic disease.