Effect of exercise to rest ratio on plasma lactate concentration at work rates above and below maximum oxygen uptake

1992 ◽  
Vol 65 (4) ◽  
pp. 365-369 ◽  
Author(s):  
Douglas L. Ballor ◽  
Anton J. Volovsek
Keyword(s):  
Oxygen Uptake ◽  
Lactate Concentration ◽  
Maximum Oxygen Uptake ◽  
Plasma Lactate ◽  
Plasma Lactate Concentration

Glucose and lactate kinetics after endotoxin administration in dogs.

1977 ◽  
Vol 232 (2) ◽  
pp. E180 ◽  
Author(s):  
R R Wolfe ◽  
D Elahi ◽  
J J Spitzer
Keyword(s):  
Lactate Concentration ◽  
Constant Infusion ◽  
Glucose Turnover ◽  
Metabolic Clearance ◽  
Plasma Lactate ◽  
Metabolic Clearance Rate ◽  
Metabolic Substrate ◽  
E Coli ◽  
Lactate Kinetics ◽  
Plasma Lactate Concentration

We studied the effects of E. coli endotoxin on the glucose and lactate kinetics in dogs by means of the primed constant infusion of [6(-3)H] glucose and Na-L-(+)-[U-14C] lactate. The infusion of endotoxin induced a transient hyperglycemic level, followed by a steady fall in plasma glucose to hypoglycemic levels. The rate of appearance (Ra) and the rate of disappearance (Rd) of glucose were both significantly elevated (P less than .05) for 150 min after endotoxin, after which neither differed from the preinfusion value. The metabolic clearance rate of glucose was significantly elevated at all times 30 min postendotoxin. By 30 min postendotoxin, Ra and Rd of lactate, plasma lactate concentration, and the percent of glucose turnover originating from lactate were significantly elevated and remained so for the duration of the experiment. We concluded that after endotoxin hypoglycemia developed because of an enhanced peripheral uptake of glucose and a failure of the liver to maintain an increased Ra of glucose. We also concluded that lactate became an important precursor for gluconeogenesis and an important metabolic substrate.

Adrenergic blockade prevents endotoxin-induced increases in glucose metabolism

1988 ◽  
Vol 255 (5) ◽  
pp. E629-E635 ◽  
Author(s):  
D. M. Hargrove ◽  
G. J. Bagby ◽  
C. H. Lang ◽  
J. J. Spitzer
Keyword(s):  
Plasma Insulin ◽  
Lactate Concentration ◽  
Insulin Concentration ◽  
Adrenergic Blockade ◽  
Plasma Lactate ◽  
Glucose Kinetics ◽  
Plasma Insulin Concentration ◽  
Beta Adrenergic ◽  
Plasma Lactate Concentration ◽  
Adrenergic Antagonists

Combined alpha- and beta-adrenergic blockade was used to investigate the role of catecholamines in endotoxin-induced elevations in glucose kinetics. Glucose kinetics were measured before and for 4 h after the injection of endotoxin [100 micrograms/100 g body wt iv, 30% lethal dose (LD30) at 24 h]. Adrenergic blockade was achieved by the bolus injection of phentolamine and propranolol followed by their continuous infusion. Endotoxin-treated rats exhibited a transient hyperglycemia and sustained (greater than 4 h) increase in plasma lactate concentration, as well as elevated rates of glucose appearance (Ra, 83%), disappearance (Rd, 58%), recycling (160%), and metabolic clearance (23%). Adrenergic blockade prevented endotoxin-induced increases in plasma glucose concentration, Ra, Rd, and recycling but not glucose clearance. The increase in plasma lactate concentration was blunted by 35%. After 2 h, endotoxic animals infused with adrenergic antagonists developed hypoglycemia, which may have resulted from an increased plasma insulin concentration. The attenuation of elevated glucose turnover by adrenergic blockade in the endotoxin-treated animals was not due to a reduction in plasma glucagon level or differences in plasma insulin concentration. Administration of the alpha- or beta-adrenergic antagonists separately blunted but did not prevent endotoxin-induced changes in glucose kinetics, and therefore the efficacy of the adrenergic blockade could not be assigned to a single receptor class. These results indicate that catecholamines are important contributory factors to many of the early alterations in carbohydrate metabolism observed during endotoxemia.

Plasma lactate and ventilation thresholds in trained and untrained cyclists

1986 ◽  
Vol 60 (3) ◽  
pp. 777-781 ◽  
Author(s):  
J. Simon ◽  
J. L. Young ◽  
D. K. Blood ◽  
K. R. Segal ◽  
R. B. Case ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Minute Ventilation ◽  
Lactate Concentration ◽  
Work Rate ◽  
Plasma Lactate ◽  
Vo2 Max ◽  
Trained Subjects ◽  
Leg Cycling ◽  
Plasma Lactate Concentration ◽  
Removal Processes

Six trained male cyclists and six untrained sedentary men were studied to determine whether the plasma lactate threshold (PLT) and ventilation threshold (VT) occur at the same work rate in both fit and unfit populations. The PLT was determined from a marked increase in plasma lactate concentration ([La]) and VT from a nonlinear increase in expired minute ventilation (VE) during incremental leg-cycling tests; work rate was increased 30 W every 2 min until volitional exhaustion. The trained subjects' mean VO2 max (63.8 ml O2 X kg-1 X min-1) and VT (65.8% VO2 max) were significantly higher (P less than 0.05) than the untrained subjects' mean VO2max (35.5 ml O2 X kg-1 X min-1) and VT (51.4% VO2 max). The trained subjects' mean PLT (68.8% VO2 max) and VT did not differ significantly, but the untrained subjects' mean PLT (61.6% VO2 max) was significantly higher than their VT. The trained subjects' mean peak [La] (10.5 mmol X l-1) did not differ significantly from the untrained subjects' mean peak [La] (11.5 mmol X l-1). However, the time of appearance of the peak [La] during passive recovery was inversely related to VO2 max. These results suggest that variance in lactate diffusion and/or removal processes between the trained and untrained subjects may account in part for the different relationships between the VT and PLT in each population.

Diving and swimming performance of white whales, Delphinapterus leucas: an assessment of plasma lactate and blood gas levels and respiratory rates.

1997 ◽  
Vol 200 (24) ◽  
pp. 3091-3099 ◽  
Author(s):  
S A Shaffer ◽  
D P Costa ◽  
T M Williams ◽  
S H Ridgway
Keyword(s):  
High Speed ◽  
Swimming Performance ◽  
Lactate Concentration ◽  
Delphinapterus Leucas ◽  
Breath Hold ◽  
Plasma Lactate ◽  
Post Exercise ◽  
Test Platform ◽  
Plasma Lactate Concentration ◽  
Breath Hold Duration

The white whale Delphinapterus leucas is an exceptional diver, yet we know little about the physiology that enables this species to make prolonged dives. We studied trained white whales with the specific goal of assessing their diving and swimming performance. Two adult whales performed dives to a test platform suspended at depths of 5-300 m. Behavior was monitored for 457 dives with durations of 2.2-13.3 min. Descent rates were generally less than 2 m s-1 and ascent rates averaged 2.2-3 m s-1. Post-dive plasma lactate concentration increased to as much as 3.4 mmol l-1 (4-5 times the resting level) after dives of 11 min. Mixed venous PO2 measured during voluntary breath-holds decreased from 79 to 20 mmHg within 10 min; however, maximum breath-hold duration was 17 min. Swimming performance was examined by training the whales to follow a boat at speeds of 1.4-4.2 m s-1. Respiratory rates ranged from 1.6 breaths min-1 at rest to 5.5 breaths min-1 during exercise and decreased with increasing swim speed. Post-exercise plasma lactate level increased to 1.8 mmol l-1 (2-3 times the resting level) following 10 min exercise sessions at swimming speeds of 2.5-2.8 m s-1. The results of this study are consistent with the calculated aerobic dive limit (O2 store/metabolic rate) of 9-10 min. In addition, white whales are not well adapted for high-speed swimming compared with other small cetaceans.

The Effect of Glycemic Index on Plasma Glucose and Lactate Levels during Incremental Exercise

2000 ◽  
Vol 10 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Stephen R. Stannard ◽  
Martin W. Thompson ◽  
Janette C. Brand Miller
Keyword(s):  
Glycemic Index ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Lactate Concentration ◽  
Incremental Exercise ◽  
Plasma Glucose Concentration ◽  
Plasma Lactate ◽  
Significant Difference ◽  
Plasma Lactate Concentration ◽  
Lactate Levels

Consumption of low glycemic index (GI) foods before submaximal endurance exercise may be beneficial to performance. To test whether this may also be true for high intensity exercise. 10 trained cyclists began an incremental exercise test to exhaustion 65 min after consuming equal carbohydrate portions of glucose (HGI), pasta (LGI), and a noncarbohydrate control (PL). Time to fatigue did not differ significantly (p = 0.05) between treatments. Plasma glucose concentration was significantly lower after LGI vs. HGI from 15 to 45 min of rest postprandial. During exercise, plasma glucose concentration was significantly lower after HGI vs. LGI from 200 W until exhaustion. Plasma lactate concentration following HGI was significantly higher than PL from 30 min of rest postprandial through to the end of the 200-W workload. Plasma lactate concentration following LGI was significantly lower than after HGI from 45 min of rest postprandial through to the end of the 100-W workload. At higher exercise intensities, there was no significant difference in plasma lactate levels between treatments. These findings suggest that a high GI carbohydrate meal (1 g/kg body wt) 65 min prior to exercise decreases plasma glucose and increases plasma lactate levels compared to a low GI meal, but not enough to be detrimental to incremental exercise performance.

The oxygen debt during routine cardiac surgery: illusion or reality?

Perfusion ◽  
2002 ◽  
Vol 17 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Y M Ganushchak ◽  
J G Maessen ◽  
D S de Jong
Keyword(s):  
Cardiac Surgery ◽  
Oxygen Uptake ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Lactate Concentration ◽  
Oxygen Debt ◽  
Plasma Lactate ◽  
Mean Values ◽  
Lactate And Pyruvate ◽  
The Mean

Background: Patients undergoing cardiac surgery with the use of cardiopulmonary bypass (CPB) are often thought to have tissue hypoxia and intraoperative oxygen debt accumulation despite the lack of sufficient data to support this assumption. Methods and results: Oxygen uptake and related parameters, including the plasma lactate and pyruvate concentrations, were studied during the peri-operative period in a group of 15 consecutive patients who underwent coronary artery bypass graft surgery. The actual oxygen uptake (VO2) and delivery (DO2) were compared with the individual expected (computed) oxygen transport values. The mean values of DO2 and VO2were in the range of the expected values. Our results demonstrate a leading role for body temperature in perioperative changes of oxygen consumption rate ( r2 = 0.65, p< 0.001). Plasma lactate and pyruvate did not exceed the physiological range in any patient. However, with initiation of CPB, the lactate to pyruvate (LA/PVA) ratio increased (from 9.87± 2.43 at T1 to 12.08± 1.51 at T2, p< 0.05). The mean value of the LA/PVA ratio was elevated during surgery. Later, upon lowering of the plasma lactate concentration in the postoperative period, the LA/PVA ratio decreased to normal values. Without any other evidence of hypoxia, this increase in the LA/PVA ratio could be explained by washout of lactate from previously hypoperfused tissues and intraoperative decrease of lactate clearance. Conclusion: Systemic oxygenation was not impaired during CPB, or during 18 h after surgery in the studied group of patients.

Effects of isolated or combined carbohydrate and caffeine supplementation between 2 daily training sessions on soccer performance

2015 ◽  
Vol 40 (5) ◽  
pp. 457-463 ◽  
Author(s):  
Victor Amorim Andrade-Souza ◽  
Romulo Bertuzzi ◽  
Gustavo Gomes de Araujo ◽  
David Bishop ◽  
Adriano Eduardo Lima-Silva
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Training Session ◽  
Rating Of Perceived Exertion ◽  
Plasma Lactate ◽  
Repeated Sprint ◽  
Plasma Lactate Concentration ◽  
Main Effects ◽  
Previous Training

This study aimed to investigate whether isolated or combined carbohydrate (CHO) and caffeine (CAF) supplementation have beneficial effects on performance during soccer-related tests performed after a previous training session. Eleven male, amateur soccer players completed 4 trials in a randomized, double-blind, and crossover design. In the morning, participants performed the Loughborough Intermittent Shuttle Test (LIST). Then, participants ingested (i) 1.2 g·kg−1 body mass·h−1 CHO in a 20% CHO solution immediately after and 1, 2, and 3 h after the LIST; (ii) CAF (6 mg·kg−1 body mass) 3 h after the LIST; (iii) CHO combined with CAF (CHO+CAF); and (iv) placebo. All drinks were taste-matched and flavourless. After this 4-h recovery, participants performed a countermovement jump (CMJ) test, a Loughborough Soccer Passing Test (LSPT), and a repeated-sprint test. There were no main effects of supplementation for CMJ, LSPT total time, or best sprint and total sprint time from the repeated-sprint test (p > 0.05). There were also no main effects of supplementation for heart rate, plasma lactate concentration, rating of perceived exertion (RPE), pleasure–displeasure, and perceived activation (p > 0.05). However, there were significant time effects (p < 0.05), with heart rate, plasma lactate concentration, RPE, and perceived activation increasing with time, and pleasure–displeasure decreasing with time. In conclusion, isolated and/or combined CHO and CAF supplementation is not able to improve soccer-related performance tests when performed after a previous training session.

Onset of submaximal exercise in thoroughbred horses

1987 ◽  
Vol 65 (10) ◽  
pp. 2513-2518 ◽  
Author(s):  
Jean-Michel Weber ◽  
Wade S. Parkhouse ◽  
Geoffrey P. Dobson ◽  
Joyce C. Harman ◽  
David H. Snow ◽  
...  
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Cardiovascular Response ◽  
Lactate Concentration ◽  
Mean Value ◽  
Plasma Lactate ◽  
Work Intensity ◽  
Thoroughbred Horses ◽  
Plasma Lactate Concentration ◽  
Intensity Of Exercise

Plasma lactate concentration, hematocrit, and heart rate were measured during a 40-min trot (3–4 m/s, 6% incline) and a 15-min canter (6.5 m/s, 0% incline) in catheterized thoroughbred horses running on a treadmill to characterize the transient changes in plasma lactate concentration during the onset of exercise, and to determine if and when a steady state was established. The intensity of exercise had an effect on the pattern of changes observed for the three variables investigated. Mean hematocrit rose from 38.5% at rest to 52.0% after a 4-min walk (1.6 m/s) and to 57.7% after 3 min of subsequent trotting (4 m/s). The highest mean value of 58.7% was reached after 3 min of cantering. A slow but significant decrease in hematocrit was measured between the time maximum levels were attained for each work intensity and the end of exercise. During the onset of submaximal work, plasma lactate concentration, hematocrit, and heart rate all reached a maximum simultaneously. The rapid cardiovascular response of thoroughbreds (strong hematocrit increase and heart-rate overshoot) did not prevent them from temporarily relying on anaerobic metabolism, as shown by a marked lactate overshoot before a steady state was established. The observed changes in lactate concentration are explained by a model predicting lactate fluxes to and from the plasma compartment during the transition from the resting steady state to the exercise steady state. Biopsies of the middle gluteal muscle were taken before and after the canter protocol to measure the metabolic intermediates of the glycogenolytic pathway. The resting and postexercise concentrations of these intermediates were not different except for a 30% reduction in glycogen. Aerobic glycogenolysis was the main pathway for energy metabolism in the middle gluteus and, as in plasma, a metabolic steady state was established in this muscle.

Low plasma lactate concentration as a biomarker of an incompetent brain-pull: A risk factor for weight gain in type 2 diabetes patients

2010 ◽  
Vol 35 (9) ◽  
pp. 1287-1293 ◽  
Author(s):  
Regina van Dyken ◽  
Christian Hubold ◽  
Sonja Meier ◽  
Britta Hitze ◽  
Aja Marxsen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Risk Factor ◽  
Weight Gain ◽  
Lactate Concentration ◽  
Plasma Lactate ◽  
Plasma Lactate Concentration ◽  
Diabetes Patients
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