Affiliations: Service d’Exploration Physiologique des Hormones et des Métabolismes, CHRU de Montpellier, F‐34059 Montpellier, France Tel.: (33) 4 67 33 82 84; Fax: (33) 4 67 33 89 63; E‐mail: drjfbrun.ephem@hol.ef | Nuclear Medicine, CHRU de Montpellier, F‐34059 Montpellier, France | Département de Physiologie, Faculté de Médecine, Institut de Biologie, F‐34060 Montpellier, France
Abstract: Since iron deficiency is associated with abnormal erythrocyte rheology, we investigated relationships between plasma ferritin and blood rheology in 36 male elite sportsmen (age: 22.38{}\pm{}0.9 years). On the whole, ferritin was negatively correlated with blood viscosity (r = -0.36, p< 0.05). When 23 subjects with low ferritin levels suggesting mild iron deficiency were compared with 13 matched sportsmen with normal ferritin levels, iron‐deficient sportsmen were shown to have a higher blood viscosity at 1000 s^{-1 } (3.17{}\pm{}0.09 vs. 2.85{}\pm{}0.06 mPa s, p< 0.05), explained by a higher plasma viscosity (1.38{}\pm{}0.02 vs. 1.31{}\pm{}0.02 mPa s, p< 0.05), while hematocrit and RBC rigidity index T_{\rm k} were similar in the two groups. RBC aggregability index M (4.59{}\pm{}0.58 vs. 2.95{}\pm{}0.43 mPa s, p< 0.05) and M_1 (8.46{}\pm{}0.58 vs. 6.07{}\pm{}0.55, p< 0.01) were higher in iron‐deficient subjects. Serum zinc was lower in iron‐deficient sportsmen (0.73{}\pm{}0.02 vs. 0.83{}\pm{}0.02 mg/l, p< 0.01), but the score of early signs of overtraining was higher in this group (10.84{}\pm{}1.61 vs. 4.08{}\pm{}1.11, p< 0.01). These data suggest that mild iron deficiency as commonly seen in athletes, before anemia occurs, is associated with an increase in plasma viscosity and RBC aggregation, together with an increased subjective feeling of exercise overload.
