Effects of short-term supervised exercise training on liver fat in adolescents with obesity: A randomized controlled trial

Authors: TAS, EMIR - University Of Pittsburgh Medical Center; LANDES, REID - University Arkansas For Medical Sciences (UAMS); DIAZ, EVA - University Arkansas For Medical Sciences (UAMS); BAI, SHASHA - Emory University; OU, XIAWEI - University Arkansas For Medical Sciences (UAMS); BUCHMANN, ROBERT - University Arkansas For Medical Sciences (UAMS); NA, XIAOXU - University Arkansas For Medical Sciences (UAMS); MUZUMDAR, RADHIKA - University Of Pittsburgh Medical Center; BØRSHEIM, ELIZABET - University Arkansas For Medical Sciences (UAMS); DRANOFF, JONATHAN - Yale School Of Medicine

Submitted to: Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2023
Publication Date: 9/20/2023
Citation: Tas, E., Landes, R.D., Diaz, E.C., Bai, S., Ou, X., Buchmann, R., Na, X., Muzumdar, R., Børsheim, E., Dranoff, J.A. 2023. Effects of short-term supervised exercise training on liver fat in adolescents with obesity: A randomized controlled trial. Obesity. 31(11):2740-2749. https://doi.org/10.1002/oby.23887.
DOI: https://doi.org/10.1002/oby.23887

Interpretive Summary: Reduced cardiorespiratory fitness (CRF) is associated with the development and progression of Non-Alcoholic Fatty Liver Disease (NAFLD) in children and adults. Improved CRF through exercise decreases liver fat in patients with NAFLD, even without clinically discernible weight loss. The present study shows that supervised exercise in the form High-Intensity Interval Training (HIIT) has beneficial effects on cardiometabolic health markers in adolescents with obesity over a 4-week intervention. Whereas the effect of HIIT on reducing liver fat was insignificant in participants with varying degrees of liver fat at baseline, HIIT can reduce liver fat percentage in those with NAFLD. HIIT is a safe and time-sparing exercise mode that can be prescribed for the treatment of metabolic complications of obesity in adolescents. Exploration of the effects of different HIIT protocols on cardiometabolic health markers in children with obesity is needed.

Technical Abstract: Objective: The trial aimed to quantify the effects of a four-week supervised high-intensity interval training (HIIT) on intrahepatic triglyceride content (IHTG, %), cardiorespiratory fitness (CRF), and cardiometabolic markers in adolescents with obesity. Design: Forty adolescents (13-18 y/o, BMI 36.7±5.8 kg/m2) with ultrasound-diagnosis of non-alcoholic fatty liver disease (NAFLD) were randomized to HIIT three times a week for 4 weeks (n=34) or observation (control; n=6). Liver magnetic resonance-imaging proton-density fat-fraction (MRI-PDFF), oral glucose tolerance test, dual-energy x-ray absorptiometry, and CRF tests were performed before and after the intervention. Within and between group differences were compared. Results: Thirteen (38%) and four (66%) children had NAFLD by MRI-PDFF (IHTG = 5%) in the HIIT and control groups, respectively. The implemented HIIT protocol had no impact on CRF nor IHTG (baseline 5.26%, delta (.)=-0.31 percentage points, 95%CI: -0.77, 0.15; p=0.179), but it decreased the 2-hour serum glucose concentration (baseline 116 mg/dL, .=-11 mg/dL; -5.5 p<0.001). When limiting the analysis to participants with NAFLD at baseline (MRI-PDFF, n=17), HIIT decreased IHTG (baseline 8.81%, .=-1.05 percentage points, 95%CI: -2.08, -0.01; p=0.048). Between group comparisons were not different. Conclusions: The implemented exercise protocol did not reduce IHTG but led to modest improvement in markers of cardiometabolic health.