Hemoglobin concentration and aerobic work capacity in women following induced erythrocythemia
The effect of induced erythrocythemia on hemoglobin concentration ([Hb]) and aerobic work capacity was determined for nine women. Cycle tests were performed at prereinfusion (T1), 2 days after a placebo infusion (T2), 2 days postreinfusion of 334 ml of red blood cells (T3), 8 days postreinfusion (T4), and 14 days postreinfusion (T5). T1 and T2 responses did not differ, negating a placebo effect. [Hb] increased from 12.7 g X dl at T1 to 14.7 g X dl at T3 and then remained constant at T4 and T5. Hematocrit increased from 38.1% at T1 to 44.9% at T3 and then remained constant at T4 and T5. Submaximal O2 uptake (VO2) and stroke volume (SV) did not change from T1 through T5. Submaximal cardiac output (Q) and heart rate (HR) decreased from T1 to T3 and then remained constant at T4 and T5. Arteriovenous O2 difference increased from T1 to T3 and then remained constant at T4 and T5. Maximal VO2 was greater at T3 (2.65 l X min-1), T4 (2.66 l X min-1), and T5 (2.60 l X min-1) than at T1 (2.41 l X min-1). Physical work capacity was greater at T3 (10,740 kg X m), T4 (10,980 kg X m), and T5 (10,380 kg X m) than at T1 (8,747 kg X m). Maximal values for Q, HR, and SV were unchanged from T1 through T5. At maximum, arteriovenous O2 difference and Hb flow rate increased from T1 to T3 and then remained constant at T4 and T5. The greater postreinfusion [Hb] improved O2 transport capacity and appeared to regulate circulatory responses.
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- "Since exercise changes blood vessel diameter , muscle blood flow, Tc and blood flow redistribution , the simple extrapolation of resting data to exercise is questionable. Accordingly, Buick et al. (1980) and Robertson et al. (1984) have determined that optimal haematocrit at rest was lower than that which obtained during exercise. While polycythaemia elevates haematocrit and blood viscosity, it has been shown that viscosity changes remain minimal for haematocrits less than 50% (Stone et al. 1968). "
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ABSTRACT: Polycythaemia has been shown to improve physical performance, possibly due to increased arterial oxygen transport. Enhanced thermoregulatory function may also accompany this manipulation, since a greater proportion of the cardiac output becomes available for heat dissipation. We further examined this possibility in five trained men, who participated in three-phase heat stress trials (20 min rest, 20 min cycling at 30% peak power (Wpeak) and 20 min at 45% Wpeak at 38.3 (SEM 0.7) degrees C [relative humidity 41.4 (SEM 2.9)%]. Trials were performed during normocythaemia (control) and polycythaemia, obtained by reinfusion of autologous red blood cells and resulting in significant elevation of arterial oxygen transport. During the polycythaemic trials, the subjects demonstrated diminished thermal strain, as evidenced by a significant reduction in cardiac frequency (fc: 12 beats.min-1 lower throughout the test; P < 0.05), and reduced auditory canal temperatures (Tac) during the latter 20-min phase (P < 0.05). Forearm sweat onset was more rapid (363.0 compared to 1083.0 s; P < 0.05), and forearm sweat rate (msw) sensitivity was elevated from 1.80 to 2.91.mg.cm-2.min-1.degrees C-1 (P < 0.05). Forehead msw was depressed during the final 20 min, while forearm msw was greater during all test phases, averaging 0.94 and 1.20 mg.cm-2.min-1, respectively, over the 60 min. Skin blood flows for the upper back, upper arm and forearm were reduced (P < 0.05). Polycythaemia enhanced thermoregulation, through an elevation in forearm sweat sensitivity and msw, but not via increased cutaneous blood flow. These modifications occurred simultaneously with decreases in fc and Tac, resulting in greater thermal tolerance.
European Journal of Applied Physiology and Occupational Physiology 09/1995; 71(5):416-23. DOI:10.1007/BF00635875
Fresenius Zeitschrift für Analytische Chemie 01/1963; 193(5):397-397. DOI:10.1007/BF00639898
Available from: Andrew John Young
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ABSTRACT: We measured the physical exercise capabilities of the U.S. Army Special Forces soldiers (male) and determined the subsequent ergogenic influence of autologous erythrocyte reinfusion. Twelve subjects (Ss) completed maximal exercise treadmill testing in a comfortable environment. Six Ss were later transfused with a 600 ml autologous erythrocyte in a NaCl glucose-phosphate solution and completed identical maximal exercise tests approximately 3 and 10 days post-transfusion. For the 6 reinfused Ss, hemoglobin (Hb) and erythrocyte volume (RCV) increased 10% (p<0.05) VO2 and 11% (p<0.05), respectively, post transfusion. We concluded that induced polycythemia can have an ergogenic effect by increasing maximal aerobic power and enhancing the thermoregulatory response during exercise-heat stress.
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