Serum ferritin in young men during prolonged heavy physical exercise.

The level of serum ferritin were investigated in 44 young men during strenuous ranger training courses lasting 4-5 d. These cadets were continuously subjected to heavy physical activities, almost without sleep and with a caloric deficit amounting to 29000-39000 kj per 24 h. Ferritin concentrations were consistently increased during the courses, and were still significantly elevated 2 d after the end of the courses. The increase of ferritin appeared to be correlated with decreased Hb values and increased total bilirubin. The results indicate that iron released from disintegrated erythrocytes probably causes increased ferritin synthesis in the reticuloendothelic cells and a subsequent release of ferritin in blood.