Vitamin C Supplementation Reduces Exercise-Induced Oxidative Stress and Increases Peak Muscular Force

Vitamin C is a popular supplement in exercise and sport for its chemical properties i.e. antioxidant capabilities. However, no clear role has been established for vitamin C supplementation (VCS) within these areas despite nearly a century’s worth of ongoing research. This study examined peak muscular pushing force (PMF) before and after a VCS intervention, 250 mg every 12 hrs for 28 days, in nine participants whom were naive to VCS and resistance exercise (RE). A dynamometer was used to perform two RE bouts, preand post-intervention, that quantified PMF during a state of exercise-induced oxidative stress (EI-OS). Saliva was collected for EIOS analysis from each participant before and after each RE bout; salivary vitamin C (VC) and free salivary malondialdehyde (MDA) were the examined biomarkers. PMF increased significantly post-intervention (405.48 ± 92.75 m·kg·s−2) from baseline (368.31 ± 76.36 m·kg·s−2, p < 0.05). MDA elevated significantly after the pre-intervention RE bout (0.385 ± 0.017 μg/mL) and the post-intervention RE bout (0.373 ± 0.014 μg/mL) compared to the baseline measures (0.373 ± 0.014 μg/mL, 0.359 ± 0.008 μg/mL; p < 0.01); a significant reduction in MDA was observed post-intervention, confirming vitamin C’s ability to reduce oxidative stress (p < 0.05). VC increased post-intervention (1.22 ± 0.73 μg/mL) from baseline (0.47 ± 0.51 μg/mL, p < 0.001). The results from this study suggest VCS is capable of increasing PMF by reducing EIOS in untrained individuals, and can be possibly used for enhancing resistance-exercise performance.