Attenuation of increase in circulating cortisol and enhancement of the acute phase protein response in vitamin C-supplemented ultramarathoners

Supplementary vitamin C (2.500 mg tablets daily) or a matched placebo was a dministered to 10 and 6 ultramarathon athletes respectively for 7 days prio r to participation in a 90 kilometer running event, as well as on the day o f the race and for 2 days after its completion. Circulating concentrations of vitamins A, C and E, as well as those of leukocytes and platelets, myelo peroxidase, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF), cortisol, and creatine kinase were measured 16 hours be fore the race and at 30 min, 24 hours, and 48 hours after completion. Pre-r ace vitamin C concentrations in the supplemented group were unchanged after the race (118.2 +/- 15.9 and 115.9 +/- 11.9 mu mol/l) while an increase wa s observed in the placebo group immediately post-race (85.8 +/- 11.9 to 107 .4 +/- 18.8 mu mol/l), with a return to pre-race values after 24 hours. Imm ediately on completion of the race transient elevations occurred in the con centrations of circulating neutrophils, monocytes and platelets, IL-6, cort isol, CRP, and creatine kinase in both groups. In the supplemented group th e concentrations of CRP were significantly higher (p < 0.01) at each of the post-race time-points while those of cortisol were 30% lower immediately p ost-race. These observations provide evidence that supplementation with vit amin C may blunt the adaptive mobilization of this vitamin from the adrenal s during exercise-induced oxidative stress and may be associated with an en hancement of the acute phase protein response and attenuation of the exerci se-induced increase in serum cortisol.