Exploring the Impact of Resistance Training at Moderate Altitude on Metabolic Cytokines in Humans: Implications for Adipose Tissue Dynamics

Hypobaric hypoxia (HH) limits oxygen supply to tissues and increases metabolic demands, especially during exercise. We studied the influence of HH exposure on the subcutaneous adipose tissue (SAT) thickness and circulating metabolic-related cytokines levels after a resistance training (R_T) program. Twenty trained men participated in a traditional hypertrophy R_T for 8 weeks (three sessions/week) under intermittent terrestrial HH (2320 m) or normoxia (N, 690 m) conditions. Before, at week 6, and after the R_T, SAT, and vastus lateralis (VL) muscle thickness were measured by ultrasound. Blood samples were taken to analyse serum cytokines (IL-6, IL-15, irisin, and myostatin) by multiplex immunoassay. Our findings revealed a moderate reduction in IL-6 and irisin in HH following the R_T (ES < -0.64; <i>p</i> < 0.05). Additionally, R_T in HH promoted serum IL-15 release (ES = 0.890; <i>p</i> = 0.062), which exhibited a trivial inverse association with the reductions observed on SAT (-17.69%; <i>p</i> < 0.001) compared with N. R_T in HH explained ~50% of SAT variance (<i>p</i> < 0.001). These results highlight the benefit of stressor factors linked to R_T in HH on SAT through the modulation of serum metabolic cytokine profiles, suggesting a potential effect on overall body composition.