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 (RBCs) from a standard 450 ml phlebotomy would increase mean power in a cycling time trial. Additionally, the study investigated whether further ABT of RBCs 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 three days before and 2 h after receiving either ~50% (135 ml) of the RBCs or a sham transfusion. On the following day, transfusion of RBCs (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 six days before and three days 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).

Conclusion: ABT of only ~135 ml of RBCs 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 RBCs does not alter 4×30 s all-out cycling performance interspersed with 4 min of recovery.