Exercise-induced oxidative stress and muscle performance in healthy women: role of vitamin E supplementation and endogenous oestradiol

Abstract

The purpose of this study was to investigate the individual and combined antioxidant effects of menstrual cycle phase-related alterations in blood serum oestradiol concentrations and of dietary vitamin E supplementation on exercise-induced oxidative stress and muscle performance. A group of 18 sedentary women, aged 19-35 years, were given supplements of 300 mg alpha-tocopherol (n = 10) or placebo (n = 8) daily during the course of two menstrual cycles. The subjects exercised the knee isokinetically to exhaustion after cycling submaximally at 50% maximal oxygen uptake during the menstrual and preovulatory phases of their menstrual cycles. Blood samples were taken before and after the exercise, to evaluate haematocrit, plasma lactic acid and malondialdehyde concentrations, erythrocyte antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and apolipoprotein B containing lipoprotein (non-high density lipoprotein, HDL, fraction) oxidation. Serum vitamin E, follicle stimulating hormone, luteinizing hormone and oestradiol concentrations were measured in pre-exercise blood samples. Neither vitamin E supplementation nor oestradiol concentrations influenced SOD and GPx activities or the susceptibility of the non-HDL fraction to oxidation while at rest. Plasma malondialdehyde concentration was unaffected by exercise, however significant reductions in erythrocyte SOD and GPx activities and increased susceptibility of the non-HDL fraction to oxidation were noted after exercise. Exercise-induced changes were reduced when oestradiol concentration was high in the preovulatory phase, independent of the serum vitamin E concentrations. In addition, both pre- (r = 0.58, P < 0.05) and post-exercise (r = 0.73, P < 0.001) GPx activities in placebo administered subjects were positively correlated with oestradiol concentrations. In conclusion, these findings suggest a better protective role of oestradiol against oxidative injury, compared to vitamin E. Exhausting muscle performance was, however, not influenced by vitamin E supplementation and/or cycle-phase related changes in oestradiol concentrations.

Does underwater rugby stimulate the over-production of reactive oxygen species?

“…Oestrogens have been shown to possess remarkable antioxidant properties and numerous investigations have been carried out to elucidate the effects of female sex hormones on lipid peroxidation. [25][26][27][28] It has been demonstrated in many animal and human studies that oestrogens have potent antioxidant property and decrease lipid peroxidation levels including LDL oxidation. 27,[28][29][30] In this present study, while oestradiol levels in female players did not significantly change, in male players the levels increased by 28.1%.…”

The Cardiovascular Effects of Chronic Hypoestrogenism in Amenorrhoeic Athletes

“…Oxidative modification of LDL vastly elevates its atherogenicity [113] and has been implicated in the initiation and progression of atherosclerosis [114]. Increasing evidence supports that oxygen-derived free radicals, namely reactive oxygen species, are associated with destructive biological processes, including DNA and cellular membrane damage [115]. Chronic age-related disease states such as diabetes and carcinogenesis, as well as strenuous physical exercise have been implicated [116,117,118].…”

“…The magnitude of the oxidative stress is determined by the capacity of the antioxidant defenses to detoxify reactive oxygen species [120A]. Intracellular enzymatic antioxidant defenses include glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase [115,121], all of which reduce the susceptibility of the cell to potentially harmful free radicals [121]. In addition, non-enzymatic extracellular antioxidant defenses also exist, including vitamin E (alpha-tocopherol), vitamin A (beta carotene), and vitamin C (ascorbic acid) [122].…”

The Role of Physical Exercise on Lipid Peroxidation in Diabetic Complications

“…It appears that the antioxidant capacity may be temporarily reduced during and immediately post exercise [77,78], after which time levels typically increase above basal conditions during the recovery period [79,80]. However, conflicting findings have been reported for each of the four main enzymes, with investigators noting increases in GPx [81,82], SOD [82,83], and CAT [70,84,85], as well as decreases in GPx [86], GR [81], SOD [78].…”