OXYGEN UPTAKE, ARTERIAL BLOOD GASES AND BLOOD LACTATE CONCENTRATION DURING SUBMAXIMAL AND MAXIMAL EXERCISE IN ADULT SUBJECTS WITH SHUNT-OPERATED TETRALOGY OF FALLOT

2009 ◽  
Vol 197 (1-6) ◽  
pp. 187-193 ◽  
Author(s):  
Bengt O. Eriksson ◽  
Björn Bjarke
Keyword(s):  
Oxygen Uptake ◽  
Tetralogy Of Fallot ◽  
Blood Lactate ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Arterial Blood

Treatment of Anaemia in Haemodialysis Patients with Erythropoietin: Long-Term Effects on Exercise Capacity

1993 ◽  
Vol 84 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Peter Báaráany ◽  
Ulla Freyschuss ◽  
Erna Pettersson ◽  
Jonas Bergström
Keyword(s):  
Oxygen Uptake ◽  
Blood Lactate ◽  
Exercise Capacity ◽  
Recombinant Human Erythropoietin ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Human Erythropoietin ◽  
Hb Concentration ◽  
Maximal Exercise Capacity

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.

Higher exercise performance and lower VO2max in Tibetan than Han residents at 4,700 m altitude

1994 ◽  
Vol 77 (2) ◽  
pp. 684-691 ◽  
Author(s):  
R. L. Ge ◽  
Q. H. Chen ◽  
L. H. Wang ◽  
D. Gen ◽  
P. Yang ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Exercise Performance ◽  
Maximal Exercise ◽  
Minute Ventilation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Blood Gases ◽  
Lower Blood ◽  
The Mean ◽  
Peripheral Adaptation

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.

Exercise recovery above and below anaerobic threshold following maximal work

1981 ◽  
Vol 51 (4) ◽  
pp. 840-844 ◽  
Author(s):  
B. A. Stamford ◽  
A. Weltman ◽  
R. Moffatt ◽  
S. Sady
Keyword(s):  
Blood Lactate ◽  
Anaerobic Threshold ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Base Line ◽  
Exercise Recovery ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Individual Subject

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.

Lactic acid infusion in dogs: effects of varying infusate pH

1983 ◽  
Vol 54 (5) ◽  
pp. 1254-1260 ◽  
Author(s):  
L. B. Gladden ◽  
J. W. Yates
Keyword(s):  
Lactic Acid ◽  
Blood Lactate ◽  
Muscle Blood Flow ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Weak Acid ◽  
Muscle Lactate ◽  
Acid Infusion ◽  
Arterial Blood ◽  
Arterial Ph

This study had two purposes: 1) to determine the effects of varying the pH of lactic acid infusion solutions on the acid-base status of anesthetized dogs, and 2) to determine the effect of elevated blood lactate concentration on muscle lactate concentration. The experiments were performed on the in situ gastro cnemius-plantaris muscle group in 14 mongrel dogs. The infusions increased the arterial blood lactate concentration to 11.0 +/- 0.5 (SE) mM after 20 min. Above an infusate pH of 4.4, the arterial pH increased by 0.118–0.167 during infusion; the arterial pH was unchanged when the infusate pH was between 3.4 and 4.0; and the arterial pH decreased as infusate pH decreased below 3.0. The effect of lactic acid infusion on blood pH appears to be the result of two opposing effects: 1) an acidifying effect due to its weak acid properties, and 2) an alkalinizing effect due to the metabolism of sodium lactate. The estimated ratio between intracellular muscle lactate and venous plasma water lactate averaged 0.647 +/- 0.038, indicative of a substantial gradient between blood and muscle. The infusion produced a significant change from lactate output to lactate uptake by the muscles. The infusion also transiently increased muscle blood flow and oxygen uptake.

Temporal sequence of recovery-related events following maximal exercise assessed by heart rate variability and blood lactate concentration

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 ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Blood Lactate ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Temporal Sequence

Effect of the blood lactate concentration on renal glutamine metabolism in dogs with chronic metabolic acidosis

1985 ◽  
Vol 63 (12) ◽  
pp. 1570-1576
Author(s):  
Mitchell L. Halperin ◽  
Ching B. Chen ◽  
Surinder Cheema-Dhadli
Keyword(s):  
Metabolic Acidosis ◽  
Blood Lactate ◽  
Filtration Rate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Glutamine Metabolism ◽  
Chronic Metabolic Acidosis ◽  
Arterial Blood ◽  
Constant Rate ◽  
Ammonium Metabolism

It appears that glutamine and lactate are the principal substrates for the kidney in dogs with chronic metabolic acidosis. Accordingly, the purpose of this study was to determine if a higher or lower rate of renal lactate extraction would influence the rate of glutamine extraction at a constant rate of renal ATP turnover. The blood lactate concentration was 0.9 ± 0.01 mM in 15 acidotic dogs. However, eight dogs with chronic metabolic acidosis had a spontaneous blood lactate concentration of 0.5 mM or lower. The kidneys of these dogs extracted considerably less lactate from the arterial blood (19 vs. 62 μmol/100 mL glomerular filtration rate (GFR)). Nevertheless, glutamine, alanine, citrate, and ammonium metabolism were not significantly different in these two groups of dogs. Renal ATP balance in acidotic dogs with a low blood lactate could only be achieved if a substrate other than additional glutamine were oxidized in that segment of the nephron which normally oxidized lactate; presumably a fat-derived substrate and (or) lactate derived from glucose was now the metabolic fuel at these more distal sites. When the blood lactate concentration was greater than 1.9 mM, lactate extraction rose to 219 μmol/100 mL GFR. Glutamine, alanine, citrate, and ammonium metabolism were again unchanged; in this case, ATP balance required substrate flux to products other than carbon dioxide, presumably, gluconeogenesis. It appears that renal ammoniagenesis is a proximal event and is independent of the rate of renal lactate extraction.

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