Nicewonger, C., Womack, C., Todd, M. K., & Flohr, J. A. (2011). The effect of iron supplementation during menses on iron markers and performance in active females. Medicine and Science in Sports and Exercise, 43(5). Supplement abstract 2005.

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"Iron deficiency without anemia is classified by normal hemoglobin levels (12+g/dL) and low serum ferritin (low is undefined) and can lead to a compromise in physical performance." This study determined the effect of seven days of iron supplementation during menses on serum ferritin, hemoglobin, physical performance, and heart rate recovery from a prescribed bout of exercise in active females (N = 10) with normal hemoglobin levels. Ss completed a graded exercise test on a treadmill and a blood draw before and after seven days of supplementation (65 mg elemental iron) or placebo. During the exercise test, Ss completed a VO2max protocol to 85% of age-predicted heart rate maximum (HRmax). Upon reaching 85% HRmax, Ss completed a 10-minute passive recovery, followed immediately by a treadmill performance test to volitional fatigue followed by a 10-minute passive recovery period. Heart rate was monitored at rest and every 15 seconds during the exercise and recovery. Following a one menstrual cycle wash out, the exercise protocol was repeated before and after the opposite treatment. Blood samples were analyzed for blood lactate, hemoglobin, and serum ferritin. Blood lactate was also measured post-exercise. Ss completed a seven-day physical activity recall and O'Connor subjective fatigue scales at each trial. Subjective muscle soreness was assessed before and after the exercise. Supplement adherence journals were collected at each post-treatment trial.

There was a significant difference in serum ferritin following seven days of iron treatment. No differences were found in serum ferritin following the placebo treatment or in hemoglobin with either treatment. Changes in blood lactate (pre- to post-exercise) were not significantly different between trials. Changes in serum ferritin were not correlated with VO2max, time to complete the graded exercise, heart rate recovery, blood lactate, muscle soreness, or fatigue.

Implication. Iron supplementation during menses was effective in raising serum ferritin levels but did not impact physical performance or heart rate recovery in active females.

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