Within-Day Timing of Concurrent Training Affects Inflammation and Body Composition in Young Adults With Obesity.

Abstract

Obesity is associated with chronic low-grade inflammation. Whether within-day organization of concurrent training influences inflammatory adaptation remains unclear. Sixty-four young adults with obesity were randomized to continuous training (CT; high-intensity functional training immediately followed by aerobic training) or separated training (ST; the same exercise volume divided into two sessions ~6 h apart). Both groups completed an 8-week intervention. Body composition and inflammatory markers were assessed before and after training using repeated-measures ANOVA. Both groups showed significant reductions in body mass, BMI, body fat mass, and BF% over time (all p < 0.05). Significant time × group interactions were observed for body mass, BMI, and body fat mass, with the CT group showing greater reductions than the ST group. IL-6 was the only inflammatory marker showing a significant interaction effect (p < 0.001), decreasing in CT while remaining unchanged in ST. TNF-α decreased significantly over time in both groups, whereas IL-10 and IL-1β showed no significant interaction effects. Within-day continuity of concurrent training reduced fat mass more than temporally separated training in young adults with obesity. An exploratory association with reduced IL-6 was observed but requires confirmation. Trial RegistrationChinese Clinical Trial Registry identifier: ChiCTR2500108145.