EXERCISE-INDUCED OXIDATIVE STRESS BEFORE AND AFTER VITAMIN-C SUPPLEMENTATION

Vitamin C (ascorbic acid) was supplemented (1 g/day) for 1 day and 2 w eeks in the same subjects. Plasma thiobarbituric acid reacting substan ces (TBARS) and oxygen radical absorbance capacity (ORAC) before and a fter 30 min submaximal exercise were measured. Different vitamin C sup plementations did not affect resting TBARS or ORAC. Following 30 min e xercise, values for TBARS were 12.6 and 33% above rest with 1 day and 2 weeks of vitamin C supplementation, respectively, compared to 46% hi gher with placebo. ORAC did not significantly change (11%) after exerc ise with a placebo, nor when subjects were given vitamin C supplements for 1 day or 2 weeks (4.9% and 5.73%, respectively). TBARS:ORAC, a ra tio representing oxidative stress, increased 32% (p<.05) with placebo compared to 5.8 and 25.8% with vitamin C supplements for 1 day and 2 w eeks, respectively. It was concluded that exercise-induced oxidative s tress was highest when subjects did not supplement with vitamin C comp ared to either 1 day or 2 weeks of vitamin C supplementation.