Key result
Acute plasma volume expansion increased V(O2peak) (4.12 vs. 3.90 l/min; P=0.006) and time to exhaustion (424 vs. 365 s; P=0.04) during high-intensity cycle exercise in young men.
Why the study?
Does acute plasma volume expansion alter VO2 kinetics, VO2peak, and exercise tolerance during high-intensity cycle exercise in young recreationally active men?
Does acute plasma volume expansion alter VO2 kinetics, VO2peak, and exercise tolerance during high-intensity cycle exercise in young recreationally active men?
Acute plasma volume expansion enhances VO2peak and exercise tolerance during high-intensity cycle exercise despite a reduction in arterial O2 content.
May enhance high-intensity exercise capacity in young men; hypothesis-generating and requires larger trials before broader application.
The purpose of this study was to examine the influence of acute plasma volume expansion (APVE) on oxygen uptake (V(O2)) kinetics, V(O2peak), and time to exhaustion during severe-intensity exercise. Eight recreationally active men performed "step" cycle ergometer exercise tests at a work rate requiring 70% of the difference between the gas-exchange threshold and V(O2max) on three occasions: twice as a "control" (Con) and once after intravenous infusion of a plasma volume expander (Gelofusine; 7 ml/kg body mass). Pulmonary gas exchange was measured breath by breath. APVE resulted in a significant reduction in hemoglobin concentration (preinfusion: 16.0 +/- 1.0 vs. postinfusion: 14.7 +/- 0.8 g/dl; P < 0.001) and hematocrit (preinfusion: 44 +/- 2 vs. postinfusion: 41 +/- 3%; P < 0.01). Despite this reduction in arterial O(2) content, APVE had no effect on V(O2) kinetics (phase II time constant, Con: 33 +/- 15 vs. APVE: 34 +/- 12 s; P = 0.74), and actually resulted in an increased V(O2peak) (Con: 3.90 +/- 0.56 vs. APVE: 4.12 +/- 0.55 l/min; P = 0.006) and time to exhaustion (Con: 365 +/- 58 vs. APVE: 424 +/- 64 s; P = 0.04). The maximum O(2) pulse was also enhanced by the treatment (Con: 21.3 +/- 3.4 vs. APVE: 22.7 +/- 3.4 ml/beat; P = 0.04). In conclusion, APVE does not alter V(O2) kinetics but enhances V(O2peak) and exercise tolerance during high-intensity cycle exercise in young recreationally active subjects.
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Berger et al. (2006) studied Healthy recreationally active men (n=8). Acute plasma volume expansion (Gelofusine) vs. Control was evaluated on V(O2peak) (l/min) (p=0.006). Acute plasma volume expansion increased V(O2peak) (4.12 vs. 3.90 l/min; P=0.006) and time to exhaustion (424 vs. 365 s; P=0.04) during high-intensity cycle exercise in young men.
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