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

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.

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.

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.

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.