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.

Blood Lactate Responses to Exercise in Children: Part 1. Peak Lactate Concentration

1997 ◽  
Vol 9 (3) ◽  
pp. 210-222 ◽  
Author(s):  
Peter Pfitzinger ◽  
Patty Freedson
Keyword(s):  
Blood Lactate ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Lactate Metabolism ◽  
Lower Blood ◽  
Peak Lactate ◽  
Peak Blood ◽  
Peak Blood Lactate

Part 1 reviews the literature concerning peak blood lactate responses to exercise in children. After a brief overview of lactate metabolism, an analysis is presented comparing children to adults regarding peak blood lactate concentration. Possible factors accounting for lower blood lactate concentrations during maximal exercise in children are considered.

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.

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.

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

Optimal Adrenergic Support in Septic Shock Due to Peritonitis

2003 ◽  
Vol 98 (4) ◽  
pp. 888-896 ◽  
Author(s):  
Qinghua Sun ◽  
Zizhi Tu ◽  
Suzana Lobo ◽  
George Dimopoulos ◽  
Nathalie Nagy ◽  
...  
Keyword(s):  
Septic Shock ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
The Other ◽  
Control Group ◽  
Lower Blood

Background The authors evaluated optimal adrenergic support using norepinephrine, dopamine, and dobutamine in a clinically relevant model of septic shock. Methods Twenty-eight mature, female, anesthetized sheep (weight, 30.5 +/- 3.6 kg) underwent cecal ligation and perforation and were randomized into four groups of seven animals to be treated with norepinephrine, dopamine-norepinephrine, dobutamine-norepinephrine, or no adrenergic agent. In all groups, lactated Ringer's solution was administered to restore cardiac filling pressures to baseline. In the norepinephrine group, norepinephrine (0.5-5 microg. kg(-1). min(-1)) was titrated to maintain mean arterial pressure between 75-85 mmHg. In the dopamine-norepinephrine group, dopamine was given first, and norepinephrine was added only when mean arterial pressure remained below 75 mmHg despite the infusion of 20 microg. kg(-1). min(-1) dopamine. In the dobutamine-norepinephrine group, dobutamine was started at the same time as norepinephrine and titrated up to 20 microg. kg(-1). min(-1) to get a 15% increase in cardiac output. Results The dobutamine-norepinephrine group had greater cardiac output; superior mesenteric blood flow, oxygen delivery (Do(2)), and oxygen consumption ([OV0312]o(2)); and lower blood lactate concentration and partial pressure of carbon dioxide (Pco(2)) gap than the controls did. Cumulative urine output was significantly higher in the dobutamine-norepinephrine group than in the other groups. Survival time was significantly longer in the dobutamine-norepinephrine (24 +/- 4 h), dopamine- norepinephrine (24 +/- 6 h), and norepinephrine (20 +/- 1 h) groups than the control group (17 +/- 2 h; P &lt; 0.05 vs. other groups), and significantly longer in the combined dopamine-norepinephrine and dobutamine-norepinephrine groups (24 +/- 5 h) than in the norepinephrine alone group (P &lt; 0.05). Histologic examination of lung biopsies revealed less severe lesions in the dobutamine-norepinephrine group than in the control and norepinephrine alone groups. Anatomic alterations in the lung, liver, and small intestine were less severe in the dobutamine-norepinephrine group than in the other groups. Conclusions In this prolonged septic shock model, association of norepinephrine with either dopamine or dobutamine resulted in the longest survival and the least severe pulmonary lesions. The combination of dobutamine with norepinephrine was associated with a better myocardial performance, greater Do(2) and [OV0312]o(2), lower blood lactate concentration and Pco(2) gap, and less anatomic injury.

Continuous increase in blood lactate concentration during different ramp exercise protocols

1989 ◽  
Vol 66 (3) ◽  
pp. 1104-1107 ◽  
Author(s):  
M. E. Campbell ◽  
R. L. Hughson ◽  
H. J. Green
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Continuous Model ◽  
Work Rate ◽  
Transformation Model ◽  
Mean Square ◽  
Log Transformation ◽  
Ramp Exercise ◽  
The Mean

The applicability of a continuous model description of the blood lactate concentration [( La-]) vs. O2 uptake (VO2) relationship was studied in nine healthy male volunteers during three different ramp exercise protocols. The work rate was increased at either 8, 15, or 50 W/min. The continuous model for [La-] = a + b exp(cVO2) was compared statistically with a previously proposed log-log transformation model for the [La-] and VO2 variables. It was found that the mean square error was significantly less for the continuous as opposed to the log-log model (P less than 0.01) by analysis of variance pooled across all three ramp slopes. The mean square errors from the individual ramp slopes were also significantly less for the continuous model by paired t test (P less than 0.05). It was observed that the major contributor to the increased error of the log-log model was at VO2's at or above the intersection point (lactate threshold) of the two linear log-transformed segments. The log-log transformation does not appear to relate to any physiological process. The lactate slope index, taken as the point where the slope of the relationship between [La-] and VO2 (i.e., d[La-]/dVO2) equaled 1, occurred at a mean VO2 of 2.25 and 2.37 l/min for the 15- and 8-W/min ramp slopes, respectively, but at 2.76 l/min for the 50-W/min ramp (P less than 0.05). It is concluded that [La-] increases as a continuous function with respect to VO2 across a wide range of ramp work rate slopes.

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
Keyword(s):  
Stroke Volume ◽  
Exercise Performance ◽  
Sham Group ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Left Lung ◽  
Blood Lactate Concentration ◽  
O2 Uptake ◽  
Group A ◽  
Exercise Induced

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.

Gas exchange and lactate anaerobic thresholds: inter- and intraevaluator agreement

1985 ◽  
Vol 58 (6) ◽  
pp. 2082-2089 ◽  
Author(s):  
L. B. Gladden ◽  
J. W. Yates ◽  
R. W. Stremel ◽  
B. A. Stamford
Keyword(s):  
Gas Exchange ◽  
Linear Regression ◽  
Computer Program ◽  
Blood Lactate ◽  
Intraclass Correlation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
The Mean ◽  
Graph Sets ◽  
Better Than

Twenty-four coded graph sets of gas exchange variables and blood lactate concentration (LA) plotted against time at 15-s intervals were analyzed by nine evaluators who determined the gas exchange (ATGE) and LA (ATLA) anaerobic thresholds. In addition, ATGE and ATLA were determined by a linear regression computer program. Agreement between ATGE and ATLA was poor; the median intraclass correlation coefficient (ri) was 0.53. Among evaluators, ATLA agreement (median ri = 0.81) was better than ATGE agreement (median ri = 0.70). In general, the ability of any evaluator to choose similar values from duplicate plots for either ATGE (median ri = 0.97) or ATLA (median ri = 0.995) was good. There was better agreement between the mean ATLA of the evaluators and the computer ATLA (ComLA) (ri = 0.88) than between the mean ATGE of the evaluators and the computer ATGE (ComVE), (ri = 0.58). Agreement between ComVE and ComLA was poor (ri = 0.29). These results suggest that ATGE does not accurately predict ATLA and that different evaluators choose different thresholds from the same data. Further assessment of the validity and precision of ATGE based on breath-by-breath and minute-by-minute data is needed.

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