Electron spin resonance spectroscopy, exercise, and oxidative stress: an ascorbic acid intervention study

topher C. Rowlands. Electron spin resonance spectroscopy, exercise, and oxidative stress: an ascorbic acid intervention study. J. Appl. Physiol. 87(6): 2032–2036, 1999.—Oxygen free radicals are highly reactive species that are produced in increased quantities during strenuous exercise and can dam-age critical biological targets such as membrane phospholip-ids. The present study examined the effect of acute ascorbic acid supplementation on exercise-induced free radical produc-tion in healthy subjects. Results demonstrate increases in the intensity of the a-phenyl-tert-butylnitrone adduct (0.05 6 0.02 preexercise vs. 0.19 6 0.03 postexercise, P 5 0.002, arbitrary units) together with increased lipid hydroperoxides (1.14 6 0.06 µmol/l preexercise vs. 1.62 6 0.19 µmol/l postexercise, P 5 0.005) and malondialdehyde (0.70 6 0.04 µmol/l preexercise vs. 0.80 6 0.04 µmol/l postexercise, P 5 0.0152) in the control phase. After supplementation with ascorbic acid, there was no significant increase in the electron spin resonance signal intensity (0.02 6 0.01 preexercise vs. 0.04 6 0.02 postexercise, arbitrary units), lipid hydroperox-ides (1.12 6 0.21 µmol/l preexercise vs. 1.12 6 0.08 µmol/l postexercise), or malondialdehyde (0.63 6 0.07 µmol/l preex-ercise vs. 0.68 6 0.05 µmol/l postexercise). The results indicate that acute ascorbic acid supplementation prevented exercise-induced oxidative stress in these subjects. lipid peroxidation; vitamin C; free radicals; superoxid