Iron Supplementation After Blood Donation Expedites Hematological Recovery but Does Not Influence Exercise Performance

Judd, TB, Shaw, KA, Krentz, JR, and Chilibeck, PD. Iron supplementation after blood donation expedites hematological recovery but does not influence exercise performance. J Strength Cond Res 39(6): 660-665, 2025-While the impact of blood donation on hemoglobin and exercise performance and the timeline for recovery is well studied, the role of iron supplementation in expediting recovery of performance is unknown. The objective of this research was to assess the effectiveness of oral iron supplementation in enhancing recovery of hemoglobin, hematocrit, and exercise performance after blood donation. Hemoglobin, hematocrit, and 5-km time trial performance were assessed in 10 moderately active subjects (6 men, 4 women; age = 34.0 ± 7.6 years, body mass = 74.4 ± 12.5 kg, V̇ o2 peak = 50.5 ± 6.0 ml·kg -1 ·min -1 ) before blood donation, the day after, and at weekly intervals for 5 weeks after donation. Before donation, individuals were stratified by sex and randomly assigned to supplement with 60 mg of elemental iron (3 men, 2 women) or placebo (3 men, 2 women) for 5 weeks. Significance was as accepted at p < 0.05. Time trial performance was decreased the day after donation by 6.7% ( p < 0.001) and returned to baseline levels by 1 week after blood donation with no difference between groups. Hemoglobin concentration decreased by 1.6 g·dl -1 after blood donation ( p < 0.01) with no difference between groups and failed to return to baseline after 5 weeks in either group. Hematocrit decreased by 4.0 and 3.1% in the iron and placebo groups, respectively, the day after donation compared with baseline ( p < 0.001). By week 4, hematocrit in the iron group was no longer different from baseline ( p = 1.0) but did not return to baseline values by week 5 in those supplementing with placebo ( p < 0.05). Iron supplementation may enhance hematological recovery after blood donation but does not influence recovery of endurance performance.