Effect of exercise during the follicular and luteal phases on indices of oxidative stress in healthy women.

PURPOSE: Eleven healthy nonsmoking women (24+/-1.1 yr) exercised for 30 min at 75-80% VO2max during the follicular (F) and luteal (L) phases of their menstrual cycle to determine whether menstrual phase influenced indices of oxidative stress. METHODS: Subjects completed the exercise in a randomized order. Subjects reported between 0800 and 0900 in a postabsorptive state, rested for 15-30 min, and had a venous blood sample obtained by Vacutainer before and after exercise. RESULTS: Resting estradiol was 54.4+/-12.0 pg.mL(-1) for F phase and was significantly higher in L phase (147.2+/-25.5 pg.mL(-1)). Plasma malondialdehyde and thiobarbituric acid substances were no different before and after exercise independent of menstrual cycle phase. No differences in resting blood total glutathione (TGSH), oxidized glutathione (GSSG), and reduced glutathione (GSH) were evident comparing the F and L phases. After exercise, TGSH decreased (P = 0.03) but reached significance only in the F phase = 8.1 %(P = 0.04), L phase = 2.5% (P = 0. 15). Exercise increased GSSG 10.5% in F (P = 0.15) and 27.8% in L phases(P = 0.01). GSH decreased after exercise independent of menstrual phase (F = 17%, L = 16%, P = 0.01). CONCLUSION: These data suggest that 30 min of moderate-intensity exercise in female subjects can result in mild oxidative stress as indicated by blood glutathione status and that menstrual cycle phase has minimal influences on these exercise responses.