Metabolic responsiveness to training depends on insulin sensitivity and protein content of exosomes in insulin-resistant males

High-intensity interval training (HIIT) improves cardiorespiratory fitness (VO2 max), but its impact on metabolism remains unclear. We hypothesized that 12-week HIIT increases insulin sensitivity in males with or without type 2 diabetes [T2D and NDM (nondiabetic humans)]. However, despite identically higher VO2 max, mainly insulin-resistant (IR) persons (T2D and IR NDM) showed distinct alterations of circulating small extracellular vesicles (SEVs) along with lower inhibitory metabolic (protein kinase C epsilon activity) or inflammatory (nuclear factor kappa B) signaling in muscle of T2D or IR NDM, respectively. This is related to the specific alterations in SEV proteome reflecting down-regulation of the phospholipase C pathway (T2D) and up-regulated antioxidant capacity (IR NDM). Thus, SEV cargo may contribute to modulating the individual metabolic responsiveness to exercise training in humans.

Automated summary

The study found that 12 weeks of high-intensity interval training can improve insulin sensitivity in males, but individuals with insulin resistance showed different alterations in metabolism and inflammatory signals. Changes in the proteome of SEVs might influence the metabolic response to exercise training in humans.