Effect of marathon and ultra-marathon on inflammation and iron homeostasis

The physiological response to high-level endurance exercise, such as running a marathon, poses several beneficial but also potentially harmful metabolic changes. The objective of this study was to determine the impact of marathon (M) and ultra-marathon (UM) on inflammation and iron homeostasis in paired samples. Fifteen well-trained, non-professional endurance athletes (14 males, 1 female) performed both a 130 km ultra-marathon and a traditional 42.195 km marathon. We determined markers of inflammation and iron homeostasis before, immediately after, and within 5 days after finishing each run, respectively. Biomarkers of inflammation (leucocytes, neutrophil granulocytes, monocytes, and c-reactive protein [CRP]) increased significantly after both marathon and ultra-marathon with higher levels of CRP after ultra-marathon compared with marathon both immediately after the race (18.15 ± 12.41 vs 5.58 ± 9.65 mg/L, P < .001) and at follow-up (15.67 ± 16.97 vs 7.19 ± 7.75 mg/L, P = .045) Concentrations of ferritin also increased significantly after both races and remained high at follow-up. Higher levels of ferritin immediately after the race (111.5 ± 103.2 vs 84.8 ± 86.3, P = .001) and at follow-up (102.7 ± 79.5 vs 74.6 ± 65.6, P = .001) were found in ultra-marathon finishers. The observed increase of serum iron and transferrin saturation (TSAT) after marathon and the decrease of serum iron and TSAT after ultra-marathon resulted in a significant absolute difference between the two races. The present data suggest a higher degree of inflammation after ultra-marathon compared with marathon. Markers of iron homeostasis also showed different response patterns with regard to running distance.