Research Article
Shuman Yang, Majken K Jensen,
Abstract
Objectives: The associations between physical activity and oxidative stress biomarkers are still controversial, and few large human studies have comprehensively investigated the relationship between physical activity and oxidative stress biomarkers. The purpose of this study was to examine the association between physical activity and oxidative stress biomarkers in a large sample of women by measuring biomarkers of both oxidation and antioxidant defense. Design and Methods: We conducted a cross-sectional study among 1,144 generally healthy women ages 43-70 years, who were included in a prospective nested case-control study of coronary heart disease in the Nurses’ Health Study. Fluorescent oxidation products (FlOPs) are oxidation markers reflecting global oxidation burden. Antioxidant defense was quantified by the activities of three major antioxidant enzymes in erythrocyte (superoxide dismutase [SOD], glutathione peroxidase [GPx] and catalase [CAT]). Self-reported physical activity was estimated in metabolic equivalents per week. Results: Physical activity was not associated with FlOP levels, or GPx and CAT activities after adjusting for covariates (all Ptrend>0.15). Higher levels of physical activity were associated with decreased SOD activity (Ptrend<0.01). We then conducted subgroup analysis of participants with and without any vigorous physical activity. Greater levels of physical activity were associated with lower SOD activity among participants with any vigorous physical activity (Ptrend=0.02). Conclusions: Greater physical activity was associated with lower SOD activity, but not with higher plasma FlOPs in generally healthy women. Our findings may be important for women to maintain a low level of oxidative stress during exercise because high oxidative stress is related to the development of many chronic diseases