Arterial Blood Lactate Concentration Research Articles

Effect of dietary modifications on lactate threshold and onset of blood lactate accumulation during incremental exercise.

To assess the effect of dietary change on (1) the point at which arterial blood lactate concentration (HLa) increases above the resting value (lactate threshold) and (2) the fixed point corresponding to 4 mM of HLa (onset of blood lactate accumulation; OBLA), five healthy male subjects were put on a mixed diet for 3 days, followed by 4 days of a low carbohydrate diet (a low CHO diet), and then 3 days of a high carbohydrate diet (a high CHO diet). Following each type of diet, the subjects performed a progressive bicycle exercise test, during which concentrations of HLa, pyruvate, FFA, and glucose were analyzed from serial samples of arterial blood, and VO2 was obtained by the Douglas bag method. The results of this study are as follows: FFA was significantly lower, while pyruvate was significantly higher at rest after a high CHO diet than after a low CHO diet (P less than 0.05). These differences continued throughout the incremental exercise, which indicates the incremental contribution of CHO to metabolism after a high CHO diet and vice versa. There was no significant difference in lactate threshold expressed in VO2 among the three conditions. VO2 obtained at OBLA was significantly lower after a high CHO diet than after a low CHO diet (P less than 0.01). It was concluded that the dietary modifications used in this study had no influence on lactate threshold but did affect the point of OBLA. Therefore, dietary conditions should be considered when OBLA is determined using a fixed 4-mM HLa method.

Effect of exercise duration during incremental exercise on the determination of anaerobic threshold and the onset of blood lactate accumulation

To determine the effect of the duration of incremental exercise on the point at which arterial blood lactate concentration (HLa) increases above the resting value (anaerobic threshold: AT) and on the point at which HLa reaches a constant value of 4 mM (onset of blood lactate accumulation: OBLA), eight male students performed two different kinds of incremental exercise. A comparison of arterial HLa and venous HLa was made under both conditions of incremental exercise. The incremental bicycle exercise tests consisted of 25 W increase every minute (1-min test) and every 4 min (4-min test). At maximal exercise, there were no significant differences in either gas exchange parameters or HLa values for the two kinds of incremental exercise. However, the peak workloads attained during the two exercises were significantly different (P less than 0.01). At OBLA and AT, there were no significant differences in gas exchange parameters during the 1-min and 4-min tests except for the workload (at OBLA P less than 0.01; at AT P less than 0.05). When venous blood HLa was used instead of arterial HLa for a 4-min test, AT was not significantly different from that obtained by arterial HLa, but OBLA was significantly different from that obtained by arterial HLa (P less than 0.05). On the other hand, for the 1-min test, venous HLa values yielded significantly higher AT and OBLA compared with those obtained using arterial HLa (P less than 0.01). It was concluded that when arterial blood was used, there was no effect of duration of workload increase in an incremental exercise test on the determination of the AT and OBLA expressed in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobic metabolism of the respiratory muscles during exercise

Although minute ventilation (VE) exhibits marked increases during heavy rhythmic exercise utilizing a large muscle mass, the extent to which this hyperpnea stresses the respiratory muscles remains controversial. In an attempt to resolve this matter, we measured arterial blood lactate concentration during seated isocapnic reproduction of peak exercise ventilation. This level of ventilation had previously been identified during a maximal 2-min treadmill run. We found that maintenance of peak exercise ventilation raised blood lactate 50% in subjects otherwise at rest (N = 8, P less than 0.01). This lactate rise occurred despite addition of CO2 to inspired gas in amounts sufficient to maintain arterial blood pH and PCO2 at resting levels, which suggests that achieving the high exercise ventilation associated with VO2max may require significant anaerobic metabolism by respiratory muscles.

Umbilical glucose and lactate extractions during maternal hyperglycemia in sheep.

Umbilical glucose and lactate extractions were determined in previously instrumented pregnant ewes into some of which D-glucose was infused to produce graded levels of maternal hyperglycemia as great as 20 mM. While fetal arterial glucose concentration continued to increase linearly as a function of maternal arterial glucose concentration during maternal hyperglycemia, the umbilical venoarterial difference in blood glucose concentration did not, and umbilical glucose extraction approached a plateau at approximately 0.063 mmol X min-1 X kg fetus-1 at maternal glucose concentrations greater than approximately 8 mM. The observed plateau in glucose extraction is consistent with saturation at high maternal glucose concentrations of the carrier mechanism for transport of glucose from the maternal to the fetal aspects of the trophoblast. The observed value of the plateau in umbilical extraction of glucose is slightly less than the maximum extraction predicted from previously published equations for this species, but the maternal blood glucose concentration at which the observed maximum occurred agrees closely with the value predicted by those equations. Umbilical lactate extraction, 0.031 +/- 0.021 mmol X min-1 X kg fetus-1, was independent of maternal arterial blood glucose and lactate concentrations and was independent of umbilical glucose extraction.

Lactic acid infusion in dogs: effects of varying infusate 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.

Endurance training regimen based upon arterial blood lactate: effects on anaerobic threshold.

The purpose of this investigation was to assess the effect of endurance training based upon the intensity as determined by the arterial blood lactate concentration (LA). Seven healthy male college students performed endurance training on a Monark bicycle ergometer for 15 min on 3 days/week for 8 weeks, at an intensity corresponding to 4 mmol X l-1 arterial blood LA determined during an incremental exercise test (25 watts increment every minute on a bicycle at 50 rpm). Another six male students served as the control group. To assess the training effect, both an incremental exercise test and a submaximal exercise test were performed before and after the endurance training. In the incremental exercise test, VO2max, VE at VO2max, anaerobic threshold (AT), and the onset of respiratory compensation for metabolic acidosis (RCMA) were measured. AT was determined as the point at which arterial LA rose above the resting value, and RCMA was determined as the point at which Paco2 decreased during the incremental exercise test. After training, AT increased significantly (37% increment expressed in VO2, p less than 0.05). There was a significant increase (p less than 0.05) in RCMA (17%) and VO2max (14%). This training decreased VO2 (4%), VE (15%), heart rate (10%), respiratory exchange ratio (5%), and LA (23%) significantly (p less than 0.05) during the submaximal exercise test after training. On the other hand, there were no significant changes in the control group through the period when the training group performed their training. These results showed that the endurance training intensity corresponding to 4 mmol X l-1 arterial blood LA was effective for the improvement in AT as well as VO2max. It is suggested that the present training regimen could delay the onset of anaerobic glycolysis, thus shifting AT to the higher workload and decreasing LA at a given submaximal exercise after training.

Acid-base imbalance in lizards during activity and recovery.

1. The effects of treadmill exercise on oxygen consumption (V02), carbon dioxide production (VCO2), arterial blood lactate concentration ([L-]a), arterial blood pH and arterial gas tensions (PaO2 and PaCO2) were measured in 3 species of lizards (Varanus salvator, V. exanthematicus, Iguana iguana) 2. Varanus salvator was exercised 45 min at an intensity which required 85% of its VO2 max. V. salvator utilized supplementary anaerobic metabolism during the first 10 min of this sustainable exercise, as evidenced by a 16 mmol/l increase in [L-]a. Respiratory exchange ratios (R, where R = VCO2/VO2) exceeded 1.2 when [L-]a and [H+]a were maximal. One half of the accumulated lactate was removed from the blood during the remainder of the 45 min exercise period, while blood pH returned to resting levels. 3. In a second set of experiments, high intensity exercise led to exhaustion after 5 to 10 min in all three species, resulting in large lactate (+ delta[L-]a = 14-20 mmol/l) and hydrogen ion (+ delta[H+]a = 23-57 nmol/l) accumulations. R values ranged from 1.2-1.8 at exhaustion. 4. Recovery from both sustainable and non-sustainable exercise was characterized as a period of rapid lactate removal. Respiratory exchange ratios were low (0.3-0.5) as metabolic CO2 was retained, replacing depleted bicarbonate stores. 5. We conclude that all three lizard species make ventilatory adjustments during and after exercise that minimize disturbances to resting hydrogen ion concentrations and acid-base balance. Varanus salvator demonstrate the ability to re-establish resting acid-base status during sustained exercise requiring 85% of their VO2,max. Changes in R appear to be a useful noninvasive indicator of net blood lactate accumulation.

Fetal myocardial oxygen and carbohydrate consumption during acutely induced hypoxemia.

Two days after catheter placement we measured the heart rate, arterial blood pressure, myocardial blood flow, and the myocardial consumption of oxygen, glucose, lactate, and pyruvate in 11 fetal sheep in utero. We then administered 8-10% oxygen to the ewe, producing a 50% decrease in oxygen content in the fetal ascending aortic blood. After 15 min of hypoxemia we repeated the measurements. Oxygen content in the fetal coronary sinus blood decreased significantly, but the arteriovenous difference of oxygen across the left ventricle also decreased during hypoxemia. Fetal myocardial blood flow increased 160% above the control level, and the myocardial oxygen consumption did not change. The systolic arterial blood pressure increased and the heart rate decreased, but cardiac work, as estimated by the rate-pressure product, was unchanged. As both fetal myocardial oxygen consumption and cardiac work did not change, myocardial oxygenation, the relationship between oxygen consumption and cardiac work, appears to be unchanged during this degree of hypoxemia. Although arterial blood glucose, lactate, and pyruvate concentrations increased significantly during hypoxemia, only the myocardial consumption of pyruvate increased; the arteriovenous difference of glucose and lactate decreased in proportion to the increase in myocardial blood flow. During hypoxemia, glucose consumption did not change, and lactate continued to be consumed rather than produced; thus it is apparent that fetal myocardial metabolism continued to be aerobic during this degree of hypoxemia. Complete oxidative combustion of the quantities of carbohydrates that were consumed would supply all of the substrate necessary to meet fetal myocardial energy demands both at rest and during hypoxemia.

Sequential perioperative lactate determination. Physiological and clinical implications.

Sequential arterial blood lactate concentrations were determined pre-, intra-, and postoperatively in 12 high risk surgical patients. These levels were correlated with simultaneous measurements of arterial blood pressure, cardiac index (CI), and oxygen consumption (VO2). There was a marked increase in lactate values intraoperatively. This increase did not correspond to decreases in either mean arterial pressure (MAP) or CI, but did appear to correlate with decreased intraoperative VO2. Postoperatively, lactate levels remained elevated, and this elevation appeared to correlate with an estimation of intraoperative oxygen deficit. CI and VO2 were increased postoperatively; the data support the hypothesis that these postoperative increases in CI and VO2 represent physiological compensations for intraoperative oxygen deficits. Clinically, determinations of lactate values may prove useful in titrating postoperative therapy to support needed physiological compensations.

Arterial versus venous blood lactate increase in the forearm during incremental bicycle exercise

Eight male subjects were studied during incremental bicycle exercise. From the forearm, arterial and venous blood lactate concentrations were measured every minute until exhaustion. There was a statistically significant difference (P<0.01) in the points at which the arterial and venous blood lactates began to increase above the resting level. The onset of increase of lactate in arterial blood occurred at 1.00±0.07 l·min−1 in\(\dot V\)O2 (mean ± SEM), which corresponded to 37.0±1.5% of\(\dot V\)O2max. Its venous counterpart occurred at 1.50±0.17 l·min−1 in\(\dot V\)O2, 55.0±3.8% of\(\dot V\)O2max. The arterio-venous lactate difference became greater after the onset of increase in arterial blood lactate (anaerobic threshold), presumably as consequence of lactate utilization by the forearm muscles.

Lactate after exercise in man: I. Evolution kinetics in arterial blood.

Arterial and venous blood lactate concentrations were measured at 10 or 30 s time intervals before, during, and after several types of muscular exercise on an ergocycle in a sitting or supine position. Arterial blood lactate concentration curves over the recovery period were found to fit a biexponential time function including a rapidly increasing and a slowly decreasing component, even during active recovery at approximately 40% VO2 max exercise. The velocity constants were dependent on the exercise load. They were also linearly related to each other. The time of lactate disappearance during recovery increased with the work load.

Conditioning Effects of Chronic Infusions of Dobutamine

We studied the conditioning effects of chronic infusion of dobutamine and exercise training in three groups of chronically instrumented dogs. One group was infused with normal saline, a second group was infused with dobutamine (40 mug/kg per min), and the third group was exercised on a treadmill at 4 mph, up a 10 degrees incline. Each group was either infused or exercised for 2 h a day, 5 d a week for 5 consecutive wk. Resting heart rate and arterial blood lactate concentration, measured at weekly intervals, decreased progressively in the dobutamine and exercise groups, but not in the group that received normal saline infusion. Cardiovascular responses to submaximal treadmill exercise were not changed by 5 wk of normal saline infusion. However, the increases in heart rate, cardiac output, mean aortic blood pressure, arterial blood lactate, plasma renin activity, and norepinephrine concentration during exercise were significantly smaller after 5 wk of conditioning with either dobutamine or exercise training. After conditioning, the increases in arteriovenous oxygen difference during exercise were larger in the latter two groups, but the increases in total body oxygen consumption did not differ before and after conditioning. To assess ventricular function, we intravenously infused methoxamine both before and after conditioning. The slope of the line that related systolic aortic blood pressure and mean left atrial pressure increased in the animals conditioned with either dobutamine or exercise, indicating enhanced myocardial contractility. Left ventricular blood flow was lower in these two groups of animals than it was in the normal saline group. Left ventricular weight did not differ among the three groups. Our results show that chronic infusion of dobutamine produced cardiovascular and metabolic conditioning effects like those produced by exercise training, and further suggest that sympathetic stimulation during exercise plays a role in physical conditioning.

Effects of azaperone on cardiovascular and respiratory functions in the horse.

1 The butyrophenone tranquilizer, azaperone, was administered intramuscularly, at dose levels of 0.4 and 0.8 mg/kg, to ponies and its effects on cardiovascular and respiratory functions assessed. 2 Arterial blood pH, CO2 tension (PaCO2) and O2 tension (PaO2) remained relatively constant throughout the course of action of azaperone. 3 Azaperone did not modify plasma protein concentration but venous blood packed cell volume and haemoglobin concentration were reduced by 5 to 10% for at least 4 hours. These changes were probably caused by uptake of erythrocytes into the splenic reservoir. 4 Small increases in heart rate occurred for up to 60 min after administration of the drug, and this was followed by a slight bradycardia in some ponies. 5 Azaperone reduced mean arterial blood pressure (MAP) for at least 4 h, by which time its ataractic action was generally no longer apparent. The hypotension was caused, during the early phase of action at least, by a reduction in peripheral resistance, since cardiac output was increased slightly 20 min after its administration. Possible mechanisms underlying the cardiovascular changes are discussed. 6 In spite of reductions in arterial blood O2 content and MAP produced by azaperone, it is likely that tissue oxygenation was adequate, since arterial blood lactate concentrations were not increased.

A Comparison In Vivo of Dacron Wool (Swank) and Polyester Mesh (Pall) Micropore Blood Transfusion Filters in the Prevention of Pulmonary Microembolism Associated with Massive Transfusion

Experiments were performed to compare the effectiveness in vivo of the two most widely used micropore blood transfusion filters in preventing detrimental physiologic changes associated with transfusion of microaggregate-containing blood. Exchange transfusion with stored blood having an elevated screen filtration pressure (SFP) through polyester mesh (Pall) filters (Group PM) was followed by decreases in arterial blood pH and O2 consumption, increases in arterial blood pyruvate and lactate concentrations, and a decrease in pulmonary DO2. The lungs of 5 of 6 animals revealed emboli far out in the pulmonary microcirculation. These changes did not occur in animals transfused through dacron wool (Swank) filters (Group DW). Even though an increase after transfusion in pulmonary Qs/Qt in Group PM did not achieve statistical significance when compared to pretransfusion Qs/Qt, it was significantly higher than that in animals in Group DW. Both filters removed considerable quantities of microaggregates; however, the polyester mesh (Pall) filters permitted passage of small microaggregates and development of ditrimental physiologic changes. Dacron wool (Swank) filters completely removed measurable microaggregates and detrimental changes did not occur.

Letter: Blood lactate response to continuous and intermittent running in the rat.

The effects of continuous and intermittent running at equal work output but varying intensities and durations upon arterial blood lactate and hematocrit concentrations were investigated in male rats. It was found that the blood lactate level was directly related to the intensity of the exercise during continuous effort and to the duration of the work during the intermittent conditions. No significant changes were found for hematocrit. This data is consistent with previous work on humans and suggest that energy sources may be preferentially manipulated during heavy intermittent work. The implication to characterizing cellular adaptation in response to training is discussed.

Exercise tolerance in chronic hypoxemia due to right-to-left shunt.

ArticleExercise tolerance in chronic hypoxemia due to right-to-left shunt.D J Strieder, Z G Mesko, A G Zaver, and W M GoldD J Strieder, Z G Mesko, A G Zaver, and W M GoldPublished Online:01 Jun 1973https://doi.org/10.1152/jappl.1973.34.6.853MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByExercise ventilatory reserve predicts survival in adult congenital heart disease associated pulmonary arterial hypertension with Eisenmenger physiologyInternational Journal of Cardiology Congenital Heart Disease, Vol. 7Efficiency of the home cardiac rehabilitation program for adults with complex congenital heart disease14 September 2018 | Congenital Heart Disease, Vol. 13, No. 6Training and Recommendations for Exercise9 September 2017Cardiopulmonary exercise testing in adults with congenital heart disease15 May 2014 | Expert Review of Cardiovascular Therapy, Vol. 12, No. 7Guidelines for Rehabilitation in Patients With Cardiovascular Disease (JCS 2012)Circulation Journal, Vol. 78, No. 8Exercise and Athletics in Adults with Congenital Heart DiseaseCyanotic Congenital Heart Disease: A Multisystem DisorderStrong and independent prognostic value of peak circulatory power in adults with congenital heart diseaseAmerican Heart Journal, Vol. 154, No. 3Usefulness of Cardiopulmonary Exercise to Predict Long-Term Prognosis in Adults With Repaired Tetralogy of FallotThe American Journal of Cardiology, Vol. 99, No. 10Abnormal Ventilatory Response to Exercise in Adults With Congenital Heart Disease Relates to Cyanosis and Predicts SurvivalCirculation, Vol. 113, No. 24Assessment of Symptoms and Exercise Capacity in Cyanotic Patients With Congenital Heart DiseaseChest, Vol. 125, No. 2Anesthetic management of the adult patient with congenital heart diseaseAnesthesiology Clinics of North America, Vol. 21, No. 3Effects of Chronic Hypoxemia on Chemosensitivity in Patients With Univentricular HeartJournal of the American College of Cardiology, Vol. 30, No. 7PHYSICAL ACTIVITY AND CONGENITAL HEART DISEASENursing Clinics of North America, Vol. 29, No. 2Exercise responses in Ebstein's anomalyProgress in Pediatric Cardiology, Vol. 2, No. 3Exercise responses in functional single ventricle before and after Fontan operationProgress in Pediatric Cardiology, Vol. 2, No. 3Cardiorespiratory responses to exercise after the Fontan operation.Circulation, Vol. 81, No. 6Exercise Tolerance and Cardiorespiratory Response to Exercise Before and After the Fontan OperationMayo Clinic Proceedings, Vol. 64, No. 12Spectrum of exercise intolerance in 45 patients with Ebstein's anomaly and observations on exercise tolerance in 11 patients after surgical repairJournal of the American College of Cardiology, Vol. 11, No. 4Dynamics of oxygen uptake during exercise in adults with cyanotic congenital heart disease.Circulation, Vol. 73, No. 6Pulmonary atresia with ventricular septal defect: Preoperative and postoperative responses to exerciseJournal of the American College of Cardiology, Vol. 7, No. 3Cardiorespiratory response to exercise in Ebstein's anomalyThe American Journal of Cardiology, Vol. 56, No. 8Recreational and Sports Recommendations for the Child with Heart DiseasePediatric Clinics of North America, Vol. 31, No. 6Functional single ventricle: Cardiorespiratory response to exerciseJournal of the American College of Cardiology, Vol. 4, No. 2Responses to ergometer exercise in a healthy biracial population of childrenThe Journal of Pediatrics, Vol. 101, No. 4Exercise Tolerance After Repair of Tetralogy of FallotThe Annals of Thoracic Surgery, Vol. 19, No. 4OXYGEN UPTAKE, ARTERIAL BLOOD GASES AND BLOOD LACTATE CONCENTRATION DURING SUBMAXIMAL AND MAXIMAL EXERCISE IN ADULT SUBJECTS WITH SHUNT-OPERATED TETRALOGY OF FALLOT24 April 2009 | Acta Medica Scandinavica, Vol. 197, No. 1-6ATP, CP, and Lactate Concentrations in Muscle Tissue during Exercise in Male Patients with Tetralogy of Fallot14 February 2011 | Scandinavian Journal of Clinical and Laboratory Investigation, Vol. 33, No. 3 More from this issue > Volume 34Issue 6June 1973Pages 853-8 https://doi.org/10.1152/jappl.1973.34.6.853PubMed4711598History Published online 1 June 1973 Published in print 1 June 1973 Metrics

Circulatory studies during physical exercise in mentally disordered patients. I. Effects of large doses of chlorpromazine.

Abstract 1. Nine patients who were not given chlorpromazine (mean age 29 years), and eight patients (mean age 30 years) who received large doses of chlorpromazine (1500–3600 mg/day) were studied, with determination of oxygen uptake, ventilation, cardiac output, arterial blood pressure and arterial blood lactate, pyruvate and noradrenaline concentrations at rest supine, and when cycling in the sitting position on a bicycle ergometer with successively increasing work loads. The heart volume was measured roentgenologically with the patient prone. 2. Four patients were studied before, and 1.5–5 months after, the beginning of chlorpromazine treatment. They maintained their physical performance during that period. 3. All patients had a low physical working capacity on the bicycle ergometer; and most of them had a reduced stroke volume in relation to the heart volume. 4. The patients treated with chlorpromazine tended to show further reduction in stroke volume and lower cardiac output during exercise than those who did not receive such treatment. 5. The arterial blood pressure at rest was largely the same in the two groups of patients, but was reduced during exercise in those treated with chlorpromazine. Chlorpromazine did not cause a significant change in peripheral vascular resistance. 6. A high blood noradrenaline level was recorded during exercise after treatment with chlorpromazine. 7. A small stroke volume, especially in patients treated with chlorpromazine, and the fall in arterial blood pressure in this group, are factors that limit physical performance. The importance is stressed of exercise tests in clinical routine in the activation of patients receiving phenothiazines, at least for those receiving large doses.