A Case–Control Study Examining the Effects of Active Versus Sedentary Lifestyles on Measures of Body Iron Burden and Oxidative Stress in Postmenopausal Women

Abstract

Approximately half of the Canadian adults have sedentary lifestyles that increase their risk of developing cardiovascular disease (CVD). Women are 10 times more likely to die from CVD than from any other disease. Their risk almost doubles with the onset of menopause, which may result in increased body iron burden and oxidative stress in sedentary women. Body iron burden may catalyze the production of cytotoxic oxygen species in vivo. We hypothesized that postmenopausal women who engage in moderate forms of aerobic exercise for at least 30 min three or more times per week would have significantly (i) lower levels of body iron burden, (ii) increased glutathione peroxidase (GPx) activity, and (iii) decreased oxidative stress in comparison to sedentary controls. An age-matched, case–control study was employed to examine the effects of active (N = 25) versus sedentary (N = 25) lifestyles in women aged 55–65 years on measures of body iron burden as quantified by total serum iron, transferrin saturation, and serum ferritin levels; GPx activity; and oxidative stress as quantified by 4-hydroxynonenal, malondialdehyde, and hexanal. Measures of body iron burden were significantly elevated in sedentary women in comparison to active women (p < .001). Red cell GPx activity was higher in active women compared to sedentary women (p < .001). Measures of oxidative stress were significantly higher in sedentary versus active women (p < .001). These findings suggest that aerobic forms of exercise may mitigate the risk of developing CVD in postmenopausal women by improving antioxidant capacity and decreasing body iron burden.