Resistance training affects iron status in older men and women

The effect of resistance training (RT) on hematological parameters and selected indices of iron status in 35 healthy older individuals was examined. Subjects included 17 postmenopausal women aged 54-71 years and 18 men aged 56-69 years. All subjects participated in RT twice weekly for 12 weeks. The RT was effective as evidenced by an increase in skeletal muscle strength for both the men and the women. Serum iron concentration as well as complete blood count values were all within normal clinical ranges and were unchanged by RT for either the men or the women. Total iron binding capacity (TIBC) decreased from 38.5 ± 8.1 to 28.0 ± 6.7 μmol/L (p<0.0001) while transferrin saturation increased from 41 ± 21 to 49 ± 22% (p=0.050) in the men. The women showed no change in TIBC (52.3 ± 13.9 to 55.2 ± 16.9 μmol/L) or transferrin saturation (21 ± 9 to 21 ± 15%). Mean serum ferritin concentration decreased from 123 ± 100 to 97 ± 73 μg/L (p=0.041, log transformed) in the women but was not changed in the men (133 ± 96 to 125 ± 103 μg/L). Conversely, transferrin receptor concentration increased in the men from 3.6 ± 1.4 to 4.9 ± 1.9 mg/L (p=0.030) but remained stable in the women (5.3 ± 1.5 to 5.3 ± 1.2 mg/L). These data indicate that with RT, iron status of older men and women change in a gender specific way.