 Subjects will be randomly assigned to receive 50 mg of ferrous sulfate 10 mg of elemental iron, 6mg of BZKL, or an identical placebo pill twice daily for 8 weeks. Subjects will be further randomly sub-divided to receive aerobic exercise training or no training during the 8-week supplementation period. At weeks 4 and 8, subjects will perform the same series of tests as was performed at baseline. The investigators hypothesize that: 1. the women who train and received iron will have smaller improvements in iron status than those who do not train 2. The women who receive iron and train will have greater improvements in physical performance than those who train and do not receive iron, and 3. The women who receive BZKL will improve their iron status or physical performance more than those who receive placebo. 