Rates of formation and oxidation of lactic acid in dogs at rest and during moderate exercise

1969 ◽  
Vol 47 (7) ◽  
pp. 603-610 ◽  
Author(s):  
Florent Depocas ◽  
Yves Minaire ◽  
Joseph Chatonnet
Keyword(s):  
Oxygen Consumption ◽  
Lactic Acid ◽  
Plasma Glucose ◽  
Energy Cost ◽  
Moderate Exercise ◽  
Plasma Lactate ◽  
Energy Cost Of Running ◽  
Extra Energy ◽  
Maximal Effort ◽  
Average Average

The rates of formation and oxidation of plasma lactic acid were measured in dogs, either resting quietly or running at 6 km/h on the level, by priming and continuous infusion with uniformly labelled 14C-lactic acid. During running at rates of oxygen consumption almost 5 times the resting value, corresponding to approximately 30% of the maximal effort, the rates of lactic acid formation and disposal were always greater than at rest and doubled on the average. Average plasma lactic acid concentrations during running were greater, equal, or lower than at rest in different dogs. The energy released by formation of the extra lactic acid from glucose during running represented, energetically, less than 0.5% of the extra energy cost of running. Seventy-four percent of the lactate formed was promptly converted to CO2, and about 12% of the respiratory carbon was derived from lactic acid in the running dogs. About 10% of the plasma glucose was derived from lactic acid during both rest and activity. At similar plasma lactate concentrations, running dogs had greater rates of formation of lactic acid than resting animals.

Energy Cost of Running in Well-Trained Athletes: Toward Slope-Dependent Factors

2021 ◽  
pp. 1-9
Author(s):  
Marcel Lemire ◽  
Romain Remetter ◽  
Thomas J. Hureau ◽  
Bernard Geny ◽  
Evelyne Lonsdorfer ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Lower Limb ◽  
Energy Cost ◽  
Cardiovascular Responses ◽  
Maximum Oxygen Consumption ◽  
Step Frequency ◽  
Physiological Factors ◽  
Vertical Stiffness ◽  
Energy Cost Of Running ◽  
Level Running

Purpose: This study aimed to determine the contribution of metabolic, cardiopulmonary, neuromuscular, and biomechanical factors to the energy cost (ECR) of graded running in well-trained runners. Methods: Eight men who were well-trained trail runners (age: 29 [10] y, mean [SD]; maximum oxygen consumption: 68.0 [6.4] mL·min−1·kg−1) completed maximal isometric evaluations of lower limb extensor muscles and 3 randomized trials on a treadmill to determine their metabolic and cardiovascular responses and running gait kinematics during downhill (DR: −15% slope), level (0%), and uphill running (UR: 15%) performed at similar O2 uptake (approximately 60% maximum oxygen consumption). Results: Despite similar O2 demand, ECR was lower in DR versus level running versus UR (2.5 [0.2] vs 3.6 [0.2] vs 7.9 [0.5] J·kg−1·m−1, respectively; all P < .001). Energy cost of running was correlated between DR and level running conditions only (r2 = .63; P = .018). Importantly, while ECR was correlated with heart rate, cardiac output, and arteriovenous O2 difference in UR (all r2 > .50; P < .05), ECR was correlated with lower limb vertical stiffness, ground contact time, stride length, and step frequency in DR (all r2 > .58; P < .05). Lower limb isometric extension torques were not related to ECR whatever the slope. Conclusion: The determining physiological factors of ECR might be slope specific, mainly metabolic and cardiovascular in UR versus mainly neuromuscular and mechanical in DR. This possible slope specificity of ECR during incline running opens the way for the implementation of differentiated physiological evaluations and training strategies to optimize performance in well-trained trail runners.

Effects of salicylates on exercise metabolism

1962 ◽  
Vol 17 (4) ◽  
pp. 665-668 ◽  
Author(s):  
John A. Downey ◽  
Robert C. Darling
Keyword(s):  
Salicylic Acid ◽  
Oxygen Consumption ◽  
Lactic Acid ◽  
Cardiovascular System ◽  
Pulmonary Ventilation ◽  
Metabolic Effects ◽  
Moderate Exercise ◽  
Young Males ◽  
Analysis Of Results ◽  
Temperature Controlled

Some metabolic effects of salicylates were measured on ten normal young males steadily performing controlled moderate exercise after administration of acetyl salicylic acid (ASA). Dosages at a rate up to 4.8 g/day were administered over lengthening periods, the last dose 1frac12–2 hr before walking on a power-driven treadmill in a temperature-controlled room. Oxygen consumption was measured, as were pulmonary ventilation, pulse rate, and blood lactic acid. While analysis of results indicated increase in resting O2 consumption within 2 hr of the first dose, no modification of O2 consumption of exercise appeared. Pulmonary ventilation was not increased after one dose, but did increase at rest, during exercise, and recovery after longer dosage; O2 extraction from each unit of ventilation increased after one dose at rest and during exercise; the extraction ratio was still increased at rest after longer administration of ASA, but decreased during exercise and recovery. Increased ventilation was predominantly effected by increased depth of respiration rather than by changes in rate. Pulse rates were not changed and no significant effects on the cardiovascular system were discerned in this respect. Submitted on March 10, 1962

Energy cost of running, cycling and swimming in young triathletes of both sexes

1999 ◽  
Vol 24 (1) ◽  
pp. 301-305
Author(s):  
V. Bunc ◽  
J. Horcic ◽  
J. Heller ◽  
J. Formánek
Keyword(s):  
Energy Cost ◽  
Energy Cost Of Running

scholarly journals Recovery heat in muscular contraction without lactic acid formation

1931 ◽  
Vol 108 (757) ◽  
pp. 279-301 ◽  
Keyword(s):  
Acetic Acid ◽  
Oxygen Consumption ◽  
Lactic Acid ◽  
Muscular Contraction ◽  
Acid Formation ◽  
Anaerobic Conditions ◽  
Spontaneous Breakdown ◽  
Rate Of Oxygen Consumption ◽  
Resting Muscle

In a comparison of muscles poisoned with mono-iodo-acetic acid (IAA) in the presence and in the absence of oxygen respectively, Lundsgaard (1930) found:- (1) That the spontaneous breakdown of phosphagen in poisoned resting muscle is much more rapid under anaerobic conditions. (2) That the onset of the characteristic contracture produced by IAA is accompanied always by an increase in the rate of oxygen consumption.

scholarly journals Examination of Potential Mechanisms in the Enhancement of Cerebral Blood Flow by Hypoglycemia and Pharmacological Doses of Deoxyglucose

1997 ◽  
Vol 17 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Naoaki Horinaka ◽  
Nicole Artz ◽  
Jane Jehle ◽  
Shinichi Takahashi ◽  
Charles Kennedy ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Glucose Metabolism ◽  
Plasma Glucose ◽  
Plasma Lactate ◽  
Insulin Hypoglycemia ◽  
Glucose Levels ◽  
Arterial Blood ◽  
Arterial Plasma

Cerebral blood flow (CBF) rises when the glucose supply to the brain is limited by hypoglycemia or glucose metabolism is inhibited by pharmacological doses of 2-deoxyglucose (DG). The present studies in unanesthetized rats with insulin-induced hypoglycemia show that the increases in CBF, measured with the [14C]iodoantipyrine method, are relatively small until arterial plasma glucose levels fall to 2.5 to 3.0 m M, at which point CBF rises sharply. A direct effect of insulin on CBF was excluded; insulin administered under euglycemic conditions maintained by glucose injections had no effects on CBF. Insulin administration raised plasma lactate levels and decreased plasma K+ and HCO3– concentrations and arterial pH. These could not, however, be related to the increased CBF because insulin under euglycemic conditions had similar effects without affecting CBF; furthermore, the inhibition of brain glucose metabolism with pharmacological doses (200 mg/kg intravenously) of DG increased CBF, just like insulin hypoglycemia, without altering plasma lactate and K+ levels and arterial blood gas tensions and pH. Nitric oxide also does not appear to mediate the increases in CBF. Chronic blockade of nitric oxide synthase activity by twice daily i.p. injections of NG-nitro-L-arginine methyl ester for 4 days or acutely by a single i.v. injection raised arterial blood pressure and lowered CBF in normoglycemic, hypoglycemic, and DG-treated rats but did not significantly reduce the increases in CBF due to insulin-induced hypoglycemia (arterial plasma glucose levels, 2.5-3 m M) or pharmacological doses of deoxyglucose.

Effect of dorsiflexion shoes on the energy cost of running

2010 ◽  
Vol 25 (2) ◽  
pp. 81-87 ◽  
Author(s):  
M. Buchheit ◽  
P.B. Laursen ◽  
F. Leblond ◽  
S. Ahmaidi
Keyword(s):  
Energy Cost ◽  
Energy Cost Of Running

scholarly journals Effects of exercise on plasma lactic acid and body temperature in man, following a standardized meal

2018 ◽  
Vol 17 (2) ◽  
pp. 270-274
Author(s):  
Tesleem K Babalola ◽  
Udoh Utibe Abasi
Keyword(s):  
Lactic Acid ◽  
Body Temperature ◽  
Statistical Tests ◽  
Medical Science ◽  
Lactate Concentration ◽  
Bicycle Ergometer ◽  
Mean Value ◽  
Plasma Lactate ◽  
Post Exercise ◽  
Before And After

Background: The effects of exercise on plasma lactic acid level and body temperature following a standardized meal were carried out on 20 healthy young individuals (aged between 18 and 29 yrs.), consisting of 10 males and 10 females. The physical fitness of the subjects was determined measuring their blood pressure, pulse rate and other physical examinations.Methodology: Each subject was made to ride the bicycle ergometer for 6mins, at a rhythmic cadence of 50revolution/ min via 100beats metronome counts. Blood samples were collected before and after the exercise to analyze for the pre and post exercise plasma lactate levels. Pre and post-exercise values for body temperature were also measured. Statistical tests were carried out at 95% CI (P=0.05).Result: The result obtained showed that exercise causes a statistically significant increase (p< 0.05) in both plasma lactate concentration (from a pre-exercise mean value of 0.98 ±0.07mmol/L to post- exercise mean value of 2.84 ±0.21mmol/L) and body temperature (from a mean value of 36.45 ±0.130C before exercise to a mean value of 36.91 ±0.190C after exercise).Conclusion: There was a statistically significant increase in plasma lactateand body temperature because of exposure to exercise which is in line with findings from most previous studies.Bangladesh Journal of Medical Science Vol.17(2) 2018 p.270-274

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