Eur J Appl Physiol. 2026 Jul 16. doi: 10.1007/s00421-026-06337-z. Online ahead of print.
ABSTRACT
PURPOSE: Acute physical exercise triggers a transient immune response. For endurance exercise, these effects are intensity-dependent. In contrast, the role of exercise intensity in resistance exercise (RE) and its contribution to immune modulation remains less understood. This randomised crossover trial aims to compare the acute effects of High-Intensity Interval Resistance Exercise (HIIRE) versus Low-Intensity Resistance Exercise (LIRE) on routine clinical cellular inflammatory markers-neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII)-in 24 healthy, RE-trained young men.
METHODS: Measurements were taken at baseline (T0), immediately post-exercise (T1), and 45 min post-exercise (T2). It was hypothesised that HIIRE would elicit a significantly greater increase in NLR, PLR, and SII from baseline (T0) to post-exercise (T1 and T2) compared to LIRE.
RESULTS: Baseline-adjusted ANCOVAs revealed significant interactions for cellular inflammatory markers (η2p = .072; NLR: p < .001, η2p = .217; PLR: p < .001, η2p = .147; SII: p < .001, η2p = .204). Post hoc analyses locate this difference for NLR, PLR, and SII 45 min post-exercise, with greater increases of HIIRE.
CONCLUSION: The results suggest a complex immune response involving pro-inflammatory signalling and immune cell redistribution induced by acute RE, with intensity being a main driver. This underscores the pivotal role of intensity in modulating acute immune responses to RE, with potential implications for exercise prescription targeting inflammatory processes.
PMID:42461394 | DOI:10.1007/s00421-026-06337-z