Acute Changes in Inflammatory Biomarker Levels in Recreational Runners Participating in a Marathon or Half-Marathon

Abstract

Background: Strenuous physical activity activates the participant's immune responses; however, few studies exist, observing exercise-induced simultaneous changes in mediators of inflammation.

Methods: We examined individual responses in soluble urokinase-type plasminogen activator receptor (suPAR), a marker of immune activation, soluble endocytic receptor for haptoglobin-hemoglobin complexes (CD163), a marker of monocyte-macrophage activation, C-reactive protein (CRP), and pro- and anti-inflammatory cytokines from blood samples drawn at baseline, at 3- and 48-h post-races from recreational runners who successfully completed the marathon (199 ± 8 min, n = 4) or half-marathon (132 ± 4 min, n = 4) run. For comparisons, biomarkers reflecting muscle, heart, kidney, and liver functions were measured.

Results: Significant 3-h post-race increases occurred in levels of suPAR (p < 0.01), CD163 (p < 0.05), white blood cells (p < 0.001), pro-inflammatory cytokines, interleukin-6 (IL-6) (p < 0.001), IL-8 (p < 0.05), and anti-inflammatory cytokine IL-10 (p < 0.05), whereas tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) remained relatively stable. Full-marathon running lead to more pronounced increases in suPAR, CD163, IL-8, and IL-10 than half-marathon running. In addition, 3-h post-race increases of all these parameters correlated significantly with changes in serum TNF-α and cortisol. The 48-h levels of serum suPAR and both pro- and anti-inflammatory cytokines had decreased to baseline levels, whereas CRP, a marker of acute phase response, increased in those with the most prominent IL-6 and IL-10 elevations in their preceding samples. The highest suPAR, CRP, IL-6, TNF-α, IL-10, and cortisol levels were noted in the individual with the most severe post-race fatigue.

Conclusions: Prolonged running increases mediators of inflammation in an exercise-dose-dependent manner which should be considered in the assessment of health status of physically active individuals after recent acute bouts of strenuous exercise.

Fig 1

Individual changes in mediators of inflammation in recreational athletes after running either a marathon or half-marathon race. *p < 0.05, **p < 0.01, and ***p < 0.001 for comparisons between pre- and post-race values of all runners at given time points. ^§ p < 0.05 and ^§§ p < 0.01 for comparisons of changes in values between full- and half-marathon runners. The highest levels of suPAR, CRP, IL-6, TNF-α, and IL-10 were noted from a marathon runner who also suffered from the most severe symptoms of post-race fatigue (case indicated by arrows). CD163 macrophage receptor for haptoglobin-hemoglobin complexes, CRP C-reactive protein, IL interleukin, suPAR soluble urokinase-type plasminogen activator receptor, TGF-β transforming growth factor-β, TNF-α tumor necrosis factor-α, WBC white blood cells (leukocytes)