Dieter Böning

Influences of exercise and endurance training on the oxygen dissociation curve of blood underin vivo andin vitro conditions

In experiments with graded exercise of 15 men (6 untrained, 3 semitrained, 6 endurance-trained) the trained subjects showed a massive shift to the right of thein vivo O2 dissociation curve (ODC) of femoral venous blood. At a saturation of 20 to 25% (18 mkp/sec)PO2 was about 9 mm Hg higher for the trained than for the untrained group. The following factors play a role: 1. The 2,3-diphosphoglycerate [2,3-DPG] concentration was increased by 15 to 20% in the trained group which explains about 2 mm Hg of the difference inPO2. 2. Exercise acidosis in the femoral venous blood depends to a large extent on CO2 in the trained, but on lactic acid in the untrained group. At low saturations the CO2-Bohr effect increases sharply thus having a greater importance in the trained subjects. This factor can explain about 2 mm Hg of the difference. However, influence of chloride and 2,3-DPG on the Bohr effect must be taken into consideration. 3. Since the large ODC-shift to the right of the trained group was not reproducible underin vitro conditions, it is suggested that a rapidly decaying unknown substance accounts for the remaining difference inPO2.

Relationships of femoral venous [K+], [H+],\(P_{o_2 } \), osmolality, and [orthophosphate] with heart rate, ventilation, and leg blood flow during bicycle exercise in athletes and non-athletes, osmolality, and [orthophosphate] with heart rate, ventilation, and leg blood flow during bicycle exercise in athletes and non-athletes

The relationship of femoral venous [K+], [H+], osmolality (OSM), PO2, and [inorganic phosphate] ([Pi]) with heart rate (HR), ventilation (VE), and calculated leg blood flow (Q) were investigated during bicycle exercise in endurance trained (TR) and untrained (UT) test subjects. At a given VO2 the increases of [K+], OSM, [Pi] and the decrease of PO2 were significantly lower in TR than in UT. In the same proportion the increases of HR, VE, and Q were diminished. Thus in TR and UT identical and highly significantly correlated regression lines of [K+], [H+], OSM, [Pi] and PO2 with HR, VE, and Q were obtained. These constituents changed in the same proportion as the relative VO2 in TR and UT. No relationships with [Na+], [Ca++], and [ Mg++] were found. By means of a multiple regression analysis the partial influence of K+, H+, OSM, PO2, and Pi upon the total change of HR, VE and Q was estimated to compare with data from infusion experiments. The findings were discussed in view of the hypothesis that these candidates may provide linkage between metabolic events, circulatory, and ventilatory adjustments during work.

Improved Physical Performance after Treatment of Renal Anemia with Recombinant Human Erythropoietin

The physical performance of 12 anemic patients on renal dialysis was investigated following treatment of renal anemia with recombinant human erythropoietin (rhEPO; 40-120 U/kg, 3 times a week). Exercise intensity at a heart rate of 130 beats/min (PWC130) on a bicycle ergometer was assessed before rhEPO treatment, after reaching the target hematocrit (73 +/- 18 days), and in the maintenance phase (211 +/- 53 days). Hemoglobin concentrations measured at these time points were 7.3 +/- 1.2, 11.9 +/- 1.5, and 12.1 +/- 1.4 g/dl, respectively. PWC130 rose from 77 +/- 27 to 104 +/- 37 and 104 +/- 51 W, respectively. Aerobic threshold (i.e. blood lactic acid concentration of 2 mmol/l) shifted to higher workloads indicating improved muscle oxygen supply.

Effect of growth hormone on exercise tolerance in children with cystic fibrosis

PURPOSE The effect of growth hormone (GH) treatment on exercise tolerance in children with cystic fibrosis was investigated. METHODS 10 prepubertal children (mean +/- SD; age: 12.1 +/- 1.7 yr; height: 137.4 +/- 9.2 cm; body mass: 27.8 +/- 4.2 kg; forced expiratory volume in 1 s (FEV1): 68 +/- 22% predicted) were randomly assigned to either control period (CON, standard therapy) or recombinant human growth hormone (GH) period (additional GH treatment, 0.11-0.14 IU.kg-1, daily, s.c.) for the first 6 months, and then assigned to the other period for the next 6 months. At study entry and after each period, anthropometric data, pulmonary function, and exercise capacity (peak exercise capacity, .VO(2peak), and isokinetic muscle strength) were measured. RESULTS Changes in height (+4.3 +/- 1.0 cm), total body mass (+2.2 +/- 0.8 kg), and lean body mass (LBM, +2.9 +/- 0.7 kg) were significantly higher (P < 0.01) after GH treatment compared with CON. Pulmonary function did not significantly change in either of the periods. In contrast to CON, GH treatment improved absolute .VO(2peak) (+19%, P < 0.01), peak ventilation (+14%, P < 0.01), and peak oxygen pulse (+18%, P < 0.01). Analysis of variance revealed that most of the changes (71%) in .VO(2peak) could be explained by those in LBM and FEV1 (P = 0.001). CONCLUSION GH treatment clearly improved exercise tolerance, presumably resulting from the combined effects of GH on the muscular, cardiovascular, and pulmonary capacity.

Heart rate and ventilation in relation to venous [K+], osmolality, pH, PCO2, PO2, [orthophosphate], and [lactate] at transition from rest to exercise in athletes and non-athletes

AbstractTo evaluate to what metabolic event in contracting muscles heart rate (HR) and

Red cell hemoglobin, hydrogen ion and electrolyte concentrations during exercise in trained and untrained subjects

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Oxygen dissociation curves in trained and untrained subjects.

E are related, time courses of femoral and cubital venous [K+], osmolality (OSM), pH, PCO2, PO2, [lactate], and [orthophosphate] ([Pi]) at onset of exercise were studied in athletes (TR) and non-athletes (UT) and compared to time courses of HR and