Oxidative stress, inflammation and recovery of muscle function after damaging exercise: effect of 6-week mixed antioxidant supplementation.
There is no consensus regarding the effects of mixed antioxidant vitamin C and/or vitamin E supplementation on oxidative stress responses to exercise and restoration of muscle function. Thirty-eight men were randomly assigned to receive either placebo group (n = 18) or mixed antioxidant (primarily vitamin C & E) supplements (n = 20) in a double-blind manner. After 6 weeks, participants performed 90 min of intermittent shuttle-running. Peak isometric torque of the knee flexors/extensors and range of motion at this joint were determined before and after exercise, with recovery of these variables tracked for up to 168 h post-exercise. Antioxidant supplementation elevated pre-exercise plasma vitamin C (93 ± 8 μmol l(-1)) and vitamin E (11 ± 3 μmol l(-1)) concentrations relative to baseline (P < 0.001) and the placebo group (P ≤ 0.02). Exercise reduced peak isometric torque (i.e. 9-19% relative to baseline; P ≤ 0.001), which persisted for the first 48 h of recovery with no difference between treatment groups. In contrast, changes in the urine concentration of F(2)-isoprostanes responded differently to each treatment (P = 0.04), with a tendency for higher concentrations after 48 h of recovery in the supplemented group (6.2 ± 6.1 vs. 3.7 ± 3.4 ng ml(-1)). Vitamin C & E supplementation also affected serum cortisol concentrations, with an attenuated increase from baseline to the peak values reached after 1 h of recovery compared with the placebo group (P = 0.02) and serum interleukin-6 concentrations were higher after 1 h of recovery in the antioxidant group (11.3 ± 3.4 pg ml(-1)) than the placebo group (6.2 ± 3.8 pg ml(-1); P = 0.05). Combined vitamin C & E supplementation neither reduced markers of oxidative stress or inflammation nor did it facilitate recovery of muscle function after exercise-induced muscle damage.
School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
David M
DM
Bailey
Clyde
C
Williams
James A
JA
Betts
Dylan
D
Thompson
Tina L
TL
Hurst
D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004338:Drug Combinations; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control / Q000534:rehabilitation; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology* / Q000503:physiopathology; D009135:Muscular Diseases / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology / Q000534:rehabilitation*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D010919:Placebos; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
D000975:Antioxidants; D004338:Drug Combinations; D010919:Placebos