Influence of resistance exercise on monocyte subtypes and intracellular immune markers in trained postmenopausal women

Abstract

Purpose: To compare the acute effects of high-load (HL) and low-load (LL) resistance exercise (RE) on circulating monocytes, their subpopulations, and intracellular expression of immunoregulatory markers (IL-10, IL-1β, TLR4, TLR6, and HSP27) in trained postmenopausal women.

Methods: Thirteen trained postmenopausal women completed two RE protocols (7 exercises): HL (90% 1RM, 6 reps, 3-min rest) and LL (50% 1RM, 20 reps, 90-s rest), in a randomized crossover design. Blood samples were collected PRE, POST, and 1H. Flow cytometry quantified monocyte subsets and the proportion of cells expressing the target markers.

Results: Circulating monocyte percentages increased significantly (P < 0.001), with a more sustained elevation after LL (P = 0.016). No major changes were seen in the overall distribution of monocyte subsets, but the intermediate-to-classical monocyte ratio decreased (P < 0.001), indicating a relative increase in classical monocytes. In non-classical monocytes, the proportion of cells expressing IL-10 (P = 0.005), total HSP27 (P = 0.016), and phosphorylated HSP27 (P < 0.001) decreased, while the proportion of IL-1β-expressing cells remained unchanged. The IL-1β to IL-10 ratio increased at 1H (P = 0.009). No changes were detected in the proportion of cells expressing TLR4 or TLR6.

Conclusion: Both HL and LL RE induced acute immunomodulatory responses with similar patterns. Load magnitude appears less influential than the RE stimulus itself in shaping monocyte-mediated immune changes.

Keywords: Cytokines; HSP27; Immune response; Monocytes; Postmenopausal women; Resistance training; TLRs.