A pilot study of cardiorespiratory fitness, adiposity, and cardiometabolic health in youth with overweight and obesity

Authors: FEARNBACH, S - Pennington Biomedical Research Center; JOHANNSEN, NEIL - Pennington Biomedical Research Center; MARTIN, CORBY - Pennington Biomedical Research Center; KATZMARZYK, PETER - Pennington Biomedical Research Center; BEYL, ROBBIE - Pennington Biomedical Research Center; HSIA, DANIEL - Pennington Biomedical Research Center; CARMICHAEL, OWEN - Pennington Biomedical Research Center; STAIANO, AMANDA - Pennington Biomedical Research Center

Submitted to: Pediatric Exercise Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2020
Publication Date: 4/25/2020
Citation: Fearnbach, S.N., Johannsen, N.M., Martin, C.K., Katzmarzyk, P.T., Beyl, R.A., Hsia, D.S., Carmichael, O.T., Staiano, A.E. 2020. A pilot study of cardiorespiratory fitness, adiposity, and cardiometabolic health in youth with overweight and obesity. Pediatric Exercise Science. 32(3):124-131. https://doi.org/10.1123/pes.2019-0192.
DOI: https://doi.org/10.1123/pes.2019-0192

Interpretive Summary: In adults, high fittness is associated with reduced mortality, even when controlling for other risk factors for cardiometabolic disease, such as whole-body adiposity. Less rigorous data is available in children, but similar concerns over measurement and how it relates to adequate risk assessment exists. Individuals with severe obesity are particularly underrepresented in exercise-based studies, limiting our understanding of the associations between cardiorespiratory fitness and cardiometabolic health in individuals with high levels of adiposity. We conducted a cross-sectional analysis of 20 youth, ranging from overweight to severe obesity, with laboratory-based measures of cardiorespiratory fitness, body composition, and cardiometabolic risk factors. In this pilot study, we found that subcutaneous adipose tissue (SAT) showed the strongest inverse association with VO2 peak, which may be partly explained by habitual sedentary time. Our results suggest that cardiorespiratory fitness may be negatively associated with SAT in adolescents ranging from overweight to severe obesity and may be partly explained by habitual sedentary activity. This work supports the need for effective childhood obesity management strategies that incorporate regular exercise in place of sedentary time. Future studies should examine the potential deleterious effects of combined high-central adiposity and low fitness on metabolic health over time, particularly through the transition from adolescence to adulthood.

Technical Abstract: To conduct a preliminary assessment of the relationships between cardiorespiratory fitness, adiposity, and cardiometabolic health using gold standard measures in diverse youth ranging from overweight to severe obesity. Twenty of 30 participants (mean [SD]; age 13.2 [1.8] y, 55% female, 45% African American) met the criteria for VO2 peak during a graded cycle ergometer test to volitional fatigue. The body composition was measured by dual-energy X-ray absorptiometry (percentage of body fat, fat mass index, and fat-free mass) and magnetic resonance imaging (abdominal visceral and subcutaneous [SAT] adipose tissue). The VO2 peak was expressed relative to fat-free mass. Fasting lipid levels, glycemic biomarkers, and vital signs were examined individually and used in a composite cardiometabolic risk score. Accelerometer-measured physical activity and sedentary time were included as covariates. VO2 peak was negatively associated with abdominal SAT (r=-.49, P<.05), but not visceral adipose tissue or markers of cardiometabolic health. The association between SAT and VO2 peak was partly explained by habitual sedentary time. We demonstrated a significant negative association between cardiorespiratory fitness and SAT in a diverse group of high-risk youth. The inclusion of rigorous, laboratory-based measures and youth with severe obesity extends the previous work in pediatric populations.