Abstract
In 110 well-trained participants of a 1000-km running competition lasting for 20 days
hematological parameters, iron metabolism, and their respective changes during the
race were investigated. Thirty-nine men and 11 women were accustomed to wholesome
vegetarian food (lacto-ovovegetarian), 52 men and 8 women consumed a conventional
western diet. In each group 50% of the runners finished the race.
Before the competition started red blood cell count, hematocrit, and hemoglobin were
on average below the values observed in the normal population in all groups. Both
male and female runners consuming the wholesome diet showed significantly lower ferritin
values than those on a western diet.
During the first days of the competition hemolysis occurred leading to increased serum
concentrations of bilirubin and iron and decreased haptoglobin levels. Hb concentrations
showed a constant decrease during the race.
Serum ferritin concentration rose about twofold within the first days and then decreased
again without reaching pre-race levels. Serum iron concentrations showed a significant
decrease between days 3 and 6.
Iron loss was caused by hematuria (25% of all urines tested), gastrointestinal blood
loss (10% of all stool specimens tested), and by sweating (4.5 µg iron/dl sweat).
Our results suggest that especially in female long-distance runners it may be difficult
to supply sufficient quantities of iron with the diet.
Key words
long-distance running - iron metabolism - hematological parameters - alimentation
- iron loss
