Cardiopulmonary adaptations to pneumonectomy in dogs. I. Maximal exercise performance

1992 ◽  
Vol 73 (1) ◽  
pp. 362-367 ◽  
Author(s):  
C. C. Hsia ◽  
L. F. Herazo ◽  
R. L. Johnson

Maximal exercise performance was evaluated in four adult foxhounds after right pneumonectomy (removal of 58% of lung) and compared with that in seven sham-operated control dogs 6 mo after surgery. Maximal O2 uptake (ml O2.min-1.kg-1) was 142.9 +/- 1.9 in the sham group and 123.0 +/- 3.8 in the pneumonectomy group, a reduction of 14% (P less than 0.001). Maximal stroke volume (ml/kg) was 2.59 +/- 0.10 in the sham group and 1.99 +/- 0.05 in the pneumonectomy group, a reduction of 23% (P less than 0.005). Lung diffusing capacity (DL(CO)) (ml.min-1.Torr-1.kg-1) reached 2.27 +/- 0.08 in the combined lungs of the sham group and 1.67 +/- 0.07 in the remaining lung of the pneumonectomy group (P less than 0.001). In the pneumonectomy group, DL(CO) of the left lung was 76% greater than that in the left lung of controls. Blood lactate concentration and hematocrit were significantly higher at exercise in the pneumonectomy group. We conclude that, in dogs after resection of 58% of lung, O2 uptake, cardiac output, stroke volume, and DL(CO) at maximal exercise were restricted. However, the magnitude of overall impairment was surprisingly small, indicating a remarkable ability to compensate for the loss of one lung. This compensation was achieved through the recruitment of reserves in DL(CO) in the remaining lung, the development of exercise-induced polycythemia, and the maintenance of a relatively large stroke volume in the face of an increased pulmonary vascular resistance.

1981 ◽  
Vol 51 (4) ◽  
pp. 840-844 ◽  
Author(s):  
B. A. Stamford ◽  
A. Weltman ◽  
R. Moffatt ◽  
S. Sady

The purpose of this study was to determine the effects of resting and exercise recovery above [70% of maximum O2 uptake (VO2 max)] and below [40% of VO2 max] anaerobic threshold (AT) on blood lactate disappearance following maximal exercise. Blood lactate concentrations at rest (0.9 mM) and during exercise at 40% (1.3 mM) and 70% (3.5 mM) of VO2 max without preceding maximal exercise were determined on separate occasions and represented base lines for each condition. The rate of blood lactate disappearance from peak values was ascertained from single-component exponential curves fit for each individual subject for each condition using both the determined and resting base lines. When determined base lines were utilized, there were no significant differences in curve parameters between the 40 and 70% of VO2 max recoveries, and both were significantly different from the resting recovery. When a resting base line (0.9 mM) was utilized for all conditions, 40% of VO2 max demonstrated a significantly faster half time than either 70% of VO2 max or resting recovery. No differences were found between 70% of VO2 max and resting recovery. It was concluded that interpretation of the effectiveness of exercise recovery above and below AT with respect to blood lactate disappearance is influenced by the base-line blood lactate concentration utilized in the calculation of exponential half times.


1994 ◽  
Vol 77 (2) ◽  
pp. 684-691 ◽  
Author(s):  
R. L. Ge ◽  
Q. H. Chen ◽  
L. H. Wang ◽  
D. Gen ◽  
P. Yang ◽  
...  

To examine the hypothesis that the pathway of adaptation to high altitude in natives differs considerably from that in newcomers, we measured maximal O2 uptake (VO2max), minute ventilation, anaerobic threshold (AT), blood lactate, and blood gases during maximal exercise in 17 lifelong Tibetan residents and 14 acclimatized Han Chinese newcomers living at the altitude of 4,700 m. The two groups were similar in age, height, and weight, and the subjects were nonathletes. Although VO2max was significantly lower in the Tibetans than in the Hans (30.4 +/- 1.5 vs. 36.0 +/- 1.9 ml.min-1.kg-1 STPD; P < 0.05), at maximal exercise effort the exercise workload was greater (167.7 +/- 4.2 vs. 150.0 +/- 5.9 W; P < 0.05). The mean AT values (in % VO2max) in the Tibetan and Han subjects were 84.1 and 61.6%, respectively (P < 0.01). Minute ventilation at maximal exercise was significantly lower in the Tibetans than in the Hans (68.4 +/- 3.4 vs. 79.7 +/- 4.1 l/min BTPS; P < 0.05), whereas heart rate at maximal effort was equivalent in the two groups. The Tibetans showed lower blood lactate value than did the Hans both before and at the end of exercise. We conclude that the Tibetan natives have higher exercise performance and AT but lower VO2max and blood lactate concentration than do acclimatized Han newcomers. These results may reflect the effects of genetic or peripheral adaptation factors in the Tibetan natives.


1984 ◽  
Vol 57 (4) ◽  
pp. 1018-1023 ◽  
Author(s):  
J. E. Caldwell ◽  
E. Ahonen ◽  
U. Nousiainen

The physiological effects on submaximal and maximal exercise of three methods commonly used by athletes for achieving rapid weight loss were determined by measuring cardiorespiratory variables in 62 nonendurance athletes. A mean weight loss of 4.1% was achieved by those who followed either a sauna (SAU), diuretic (DIU), or exercise (ACT) protocol, compared with the average weight loss of 1.2% in the control group. At maximal exercise O2 consumption, O2 pulse, blood lactate concentration, and work load decreased in SAU and DIU groups relative to the ACT group, whereas only a few differences were observed at the aerobic threshold. Weight loss achieved over a 48-h period was less detrimental to an athlete than was a more rapid (24-h) weight reduction achieved through sauna bathing or the use of diuretics. We conclude that not only the quantity of weight loss but also the method itself may limit physical performance.


2020 ◽  
Vol 6 (1) ◽  
pp. e000815
Author(s):  
Mette Engan ◽  
Ida Jansrud Hammer ◽  
Trine Stensrud ◽  
Hilde Gundersen ◽  
Elisabeth Edvardsen ◽  
...  

ObjectiveTo evaluate changes in pulmonary function and feasibility of portable continuous laryngoscopy during maximal uphill running.MethodsHealthy volunteers participated in an uphill race. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were obtained before and 5 and 10 min after finishing the race. Capillary blood lactate concentration ([BLa-]) and Borg score for perceived exertion were registered immediately after the race. One participant wore a portable video-laryngoscope during the race, and the video was assessed for technical performance.ResultsTwenty adult subjects participated with a mean (SD) age of 40.2 (9.7) years. Mean (SD) race duration and post-exercise [BLa-] was 13.9 (2.3) min and 10.7 (2.1) mmol/L, respectively, and the median (range) Borg score for perceived exertion was 9 (5–10). Mean percentage change (95% CI) 5 and 10 min post-exercise in FEV1 were 6.9 (3.7 to 10.2) % and 5.9 (2.7 to 9.0) %, respectively, and in FVC 5.2 (2.3 to 8.1) % and 4.7 (1.6 to 7.9) %, respectively. The recorded video of the larynx was of good quality.ConclusionsMaximal aerobic field exercise induced bronchodilatation in the majority of the healthy non-asthmatic participants. It is feasible to perform continuous video-laryngoscopy during heavy uphill exercise.


1987 ◽  
Vol 62 (2) ◽  
pp. 545-550 ◽  
Author(s):  
P. A. Deuster ◽  
E. Dolev ◽  
S. B. Kyle ◽  
R. A. Anderson ◽  
E. B. Schoomaker

This study was conducted to determine whether short-term, high-intensity anaerobic exercise alters Mg homeostasis. Thirteen men performed intermittent bouts of treadmill running at 90% of their predetermined maximum O2 uptake until exhaustion on one occasion during a week in which all men were consuming a standard diet (115 mg Mg/1,000 kcal). Plasma and erythrocyte Mg concentrations and peripheral blood mononuclear cell Mg content were measured before and after the exercise. Complete 24-h urine collections were obtained on control days, on the day of exercise, and on the day after exercise. Exercise induced a transient but significant decrease in plasma Mg content (-6.8%; P less than 0.01); over 85% of the loss could be accounted for by a shift to the erythrocytes. Significant increases in urinary excretion of Mg were observed on the day of exercise (131.5 +/- 6.8 mg/day) compared with control days (108 +/- 6.6 mg/day), with the percent increase correlating with postexercise blood lactate concentration (r = 0.68; P less than 0.01) and oxygen consumption during recovery (r = 0.84; P less than 0.001). The data indicate that high-intensity anaerobic exercise induces intercompartmental Mg shifts in blood that return to preexercise values within 2 h and urinary losses on the day of exercise that return to base line the day after exercise. It is postulated that the exercise-induced increase in Mg excretion may depend on the intensity of the exercise, and the relative contribution of anaerobic metabolism to the total energy expended during exercise.


1993 ◽  
Vol 84 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Peter Báaráany ◽  
Ulla Freyschuss ◽  
Erna Pettersson ◽  
Jonas Bergström

1. The effects of correcting anaemia on exercise capacity were evaluated in 21 haemodialysis patients (aged 39 ± 12 years) before starting treatment with recombinant human erythropoietin (Hb concentration, 73 ± 10 g/l; total Hb, 59 ± 12% of expected), after correction of the anaemia to a Hb concentration of 108 ± 7 g/l and a total Hb 82 ± 10% of expected, and in 13 of the patients after 12 months on maintenance recombinant human erythropoietin treatment (Hb concentration 104 ± 14 g/l, total Hb 79 ± 17% of expected). Fifteen healthy subjects (aged 41 ± 9 years), who took no regular exercise, constituted the control group. Maximal exercise capacity was determined on a bicycle ergometer. Oxygen uptake, respiratory quotient, blood lactate concentration, heart rate and blood pressure were measured at rest and at maximal workload. 2. After 6 ± 3 months on recombinant human erythropoietin, maximal exercise capacity increased from 108 ± 27 W to 130 ± 36 W (P < 0.001) and the maximal oxygen uptake increased from 1.24 ± 0.39 litres/min to 1.50 ± 0.45 litres/min (P < 0.001). No significant changes in respiratory quotient (1.16 ± 0.13 versus 1.18 ± 0.13) and blood lactate concentration (4.0 ± 1.8 versus 3.6 ± 1.1 mmol/l) at maximal workload were observed, but the blood lactate concentration in the patients was significantly lower than that in the control subjects (6.7 ± 2.3 mmol/l, P < 0.01). After the correction of anaemia, the aerobic power was still 38% lower in the patients than in the control subjects and 17% lower than the reference values. 3. After 12 months on maintenance recombinant human erythropoietin treatment (17 ± 3 months from the start of the study), no further significant changes were observed in maximal exercise capacity (before start, 112 ± 31 W, 6 ± 3 months, 134 ± 42 W, 17 ± 3 months, 134 ± 50 W), maximal oxygen uptake (before start, 1.33 ± 0.45 litres/min; 6 ± 3 months, 1.59 ± 0.54 litres/min; 17 ± 3 months, 1.75 ± 0.78 litres/min) or blood lactate concentration (before start, 4.4 ± 1.9 mmol/l; 6 ± 3 months, 4.0 ± 1.0 mmol/l; 17 ± 3 months, 4.7 ± 2.0 mmol/l). 4. Thus, in haemodialysis patients the improvement in maximal aerobic power after the correction of anaemia persists without marked changes during long-term treatment with recombinant human erythropoietin. We did not observe any effects on exercise capacity that could be attributed to a spontaneous increase in physical activity after treatment of anaemia.


2016 ◽  
Vol 37 (5) ◽  
pp. 536-543 ◽  
Author(s):  
Rosangela Akemi Hoshi ◽  
Luiz Carlos Marques Vanderlei ◽  
Moacir Fernandes de Godoy ◽  
Fábio do Nascimento Bastos ◽  
Jayme Netto ◽  
...  

1993 ◽  
Vol 3 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Mikael Fogelholm ◽  
Inkeri Ruokonen ◽  
Juha T. Laakso ◽  
Timo Vuorimaa ◽  
Jaakko-Juhani Himberg

By means of a 5-week vitamin B-complex .supplementation, associations between indices of vitamin B1, B2, and B6, status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18–32 yrs), were randomized into vitamin (n=22) and placebo (n=20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p<0.0001) after supplementation: transketolase decreased from l. 16 (1.14–1.18) (mean and 95% confidence interval) to 1.08 (1.06–1.10); glutathione reductase decreased from 1.33 (1.28–1.39) to 1 .I4 (1.1 1–1.17); and aspartate aminotransferase decreased from 2.04 (1.94–2.14) to 1.73 (1.67–1.80). No changes were found after placebo. Despite improved indices of vitamin status, supplementation did not affect exercise-induced blood lactate concentration. Hence no association was found between ACs and blood lactate. It seems that marginally high ACs do not necessarily predict altered lactate metabolism.


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