Effects of Iron Supplementation on Total Body Hemoglobin During Endurance Training at Moderate Altitude

The aim of the study was to test the hypotthesis that iron supplementation in well-trained non-iron-depleted athletes leads to an enhanced increase of total body hermoglobin (TBH) during training at moderate altitude. Therefore., the members of the national German boxing team were rancHomly assigned to treatment with ferrous-glycine-sulfate (1335 mg equivalent to 200mg elementary iron daily) or with placebo during 18 days of endurance training at moderate altitude (1800 m). Before and after altitude training TBH was determiined by CO-re-breathing, measures of exercise performance were determined with an incremental treadmill test. Before, durinig and after the stay at moderate altitude erythropoietin (Epo)), reticulocytes (Retics) and parameters of iron metabolism werre measured in venous blood. The results show that TBH did not change significantly in the placebo-group and even slightly, biut significantly decreased in the iron-treated group. However, tlhere was a significant increase of Epo and Retics in both groups during training at moderate altitude whereas parameters <of iron metabolism remained unchanged. V02max did not ch.ange either. To test whether a training-induced hemolysis, an increased urinary iron excretion or gastrointestinal blood loss coiuld explain the unexpected drop of TBH we tested most of the boxers again during a similar training camp at low altitude (400-1000 m) to obtain measures of hemolysis, urinary iron excretion and occult hemoglobin loss with the stools. Although there w/ere signs of an increased erythrocyte turnover no iron loss coulld be observed. We conclude that 18 days of endurance training at an altitude of 1800 m does not lead to an increase of TBH in mon-iron-depleted athletes with and without iron supplementation.

Key words

Altitude - blood volume - training - s,ports - iron