Time Trial Performance Is Sensitive to Low-Volume Autologous Blood Transfusion.

PURPOSE: This study tested the hypothesis that autologous blood transfusion (ABT) of ~50% of the red blood cells (RBC) from a standard 450-mL phlebotomy would increase mean power in a cycling time trial. In addition, the study investigated whether further ABT of RBC obtained from another 450-mL phlebotomy would increase repeated cycling sprint ability. METHODS: In a randomized, double-blind, placebo-controlled crossover design (3-month wash-out), nine highly trained male subjects donated two 450-mL blood bags each (BT trial) or were sham phlebotomized (PLA trial). Four weeks later, a 650-kcal time trial (n = 7) was performed 3 d before and 2 h after receiving either ~50% (135 mL) of the RBC or a sham transfusion. On the following day, transfusion of RBC (235 mL) from the second donation or sham transfusion was completed. A 4 × 30-s all-out cycling sprint interspersed by 4 min of recovery was performed 6 d before and 3 d after the second ABT (n = 9). RESULTS: The mean power was increased in time trials from before to after transfusion (P < 0.05) in BT (213 ± 35 vs 223 ± 38 W; mean ± SD) but not in PLA (223 ± 42 vs 224 ± 46 W). In contrast, the mean power output across the four 30-s sprint bouts remained similar in BT (639 ± 35 vs 644 ± 26 W) and PLA (638 ± 43 vs 639 ± 25 W). CONCLUSIONS: ABT of only ~135 mL of RBC is sufficient to increase mean power in a 650-kcal cycling time trial by ~5% in highly trained men. In contrast, a combined high-volume transfusion of ~135 and ~235 mL of RBC does not alter 4 × 30-s all-out cycling performance interspersed with 4 min of recovery.