Naval Health Research Center Effect of Induced Erythrocythemia on Aerobic Capacity, Ventilatory Threshold, and Run Performance

Purpose: To determine the effects of induced erythrocythemia upon aerobic capacity (VO^), ventilatory threshold (VT), and aerobic performance (3-mile track run, [3MT]). Methods: Six trained male distance runners (age = 34.8 ± 5 yr, hematocrit [Hct] = 39.6 ± 1.8%, V02max= 4.10 ± 0.56 L 02 • min ), received two infusion treatments in a double-blind, counterbalanced study. Treatments: 760 mL autologous resuspended red blood cells (Hct = 43.5%) (BT) and 250 mL isotonic saline (ST) were administered 7 days apart. Results: BT significantly (P < 0.01) increased V02max (0.46 ± 0.2 L 02 • min ), VT (0.36 ± 0.23 L 02 • min' ), and significantly (P < 0.05) decreased 3MT time (19.8 ± 16.0 s or 2.0 ± 1.6%). Blood lactate after treadmill tests (8.0 ± 2.0 mmol-L") were unchanged by BT but were significantly (P < 0.01) lower at rest. Hct was unchanged 24 h following BT, but a wk later had increased significantly (P < 0.05) to 44.0%. The delayed increase in Hct suggests an initial increase in blood volume may have contributed to the increase in VO^ at 24 h. ST had no significant effects on any measure. Hct and VOj,,^ were not different from baseline 4 wk after BT. Blood parameters did not change significantly (P > 0.05) after BT; ATP, 2,3-DPG, p-50, MCV, MCH, MCHC, RBCs, and WBCs. Reticulocytes were depressed significantly (P < 0.05) (0.28 ± 0.2%) 2 wk after BT, but were normal (0.5 ± 0.2%) all other times. Conclusion: Blood loading increases VO^ and enhances aerobic performance (3 mile run). Selected hematological parameters remain normal at all times.