by Edmund R. Burke, Ph.D.
An estimated 3-5% of U.S. women (ages 18-44) have iron deficiency anemia, while three times this amount are in the earlier stage of iron deficiency and have not yet progressed to anemia. Furthermore, aerobic exercise is a drain on iron stores in the body, so many young women may be at risk for iron deficiency. A study from Cornell University researchers compared the effects of daily iron supplements in 42 iron-depleted (but non-anemic) women. The women in this six-week double-blind trial exercised 30 minutes per day, five days per week. The time it took to complete a 15-kilometer cycle test was compared at the start and end of the study. The women taking the iron supplements showed a greater improvement in cycle time, compared to the placebo group. This result supports the notion that iron deficiency, even if anemia is not present, impairs exercise performance in women.