Pyruvate shuttling during rest and exercise before and after endurance training in men

2004 ◽  
Vol 97 (1) ◽  
pp. 317-325 ◽  
Author(s):  
Gregory C. Henderson ◽  
Michael A. Horning ◽  
Steven L. Lehman ◽  
Eugene E. Wolfel ◽  
Bryan C. Bergman ◽  
...  
Keyword(s):  
Endurance Training ◽  
Exercise Intensity ◽  
Glycolytic Flux ◽  
Arterial Lactate ◽  
Arterial Blood ◽  
Before And After ◽  
Isotopic Equilibration ◽  
Lactate And Pyruvate ◽  
Net Release ◽  
Rest And Exercise

We describe the isotopic exchange of lactate and pyruvate after arm vein infusion of [3-13C]lactate in men during rest and exercise. We tested the hypothesis that working muscle (limb net lactate and pyruvate exchange) is the source of the elevated systemic lactate-to-pyruvate concentration ratio (L/P) during exercise. We also hypothesized that the isotopic equilibration between lactate and pyruvate would decrease in arterial blood as glycolytic flux, as determined by relative exercise intensity, increased. Nine men were studied at rest and during exercise before and after 9 wk of endurance training. Although during exercise arterial pyruvate concentration decreased to below rest values ( P < 0.05), pyruvate net release from working muscle was as large as lactate net release under all exercise conditions. Exogenous (arterial) lactate was the predominant origin of pyruvate released from working muscle. With no significant effect of exercise intensity or training, arterial isotopic equilibration [(IEpyruvate/IElactate)·100%, where IE is isotopic enrichment] decreased significantly ( P < 0.05) from 60 ± 3.1% at rest to an average value of 12 ± 2.7% during exercise, and there were no changes in femoral venous isotopic equilibration. These data show that 1) the isotopic equilibration between lactate and pyruvate in arterial blood decreases significantly during exercise; 2) working muscle is not solely responsible for the decreased arterial isotopic equilibration or elevated arterial L/P occurring during exercise; 3) working muscle releases similar amounts of lactate and pyruvate, the predominant source of the latter being arterial lactate; 4) pyruvate clearance from blood occurs extensively outside of working muscle; and 5) working muscle also releases alanine, but alanine release is an order of magnitude smaller than lactate or pyruvate release. These results portray the complexity of metabolic integration among diverse tissue beds in vivo.

scholarly journals Endurance training increases gluconeogenesis during rest and exercise in men

2000 ◽  
Vol 278 (2) ◽  
pp. E244-E251 ◽  
Author(s):  
Bryan C. Bergman ◽  
Michael A. Horning ◽  
Gretchen A. Casazza ◽  
Eugene E. Wolfel ◽  
Gail E. Butterfield ◽  
...  
Keyword(s):  
Endurance Training ◽  
Relative Intensity ◽  
Lactate Concentration ◽  
Cycle Ergometer ◽  
Cycle Ergometry ◽  
Glucose Turnover ◽  
Arterial Lactate ◽  
Before And After ◽  
Arterial Glucose ◽  
Rest And Exercise

The hypothesis that endurance training increases gluconeogenesis (GNG) during rest and exercise was evaluated. We determined glucose turnover with [6,6-2H]glucose and lactate incorporation into glucose by use of [3-13C]lactate during 1 h of cycle ergometry at two intensities [45 and 65% peak O2 consumption (V˙o 2 peak)] before and after training [65% pretrainingV˙o 2 peak], same absolute workload (ABT), and 65% posttrainingV˙o 2 peak, same relative intensity (RLT). Nine males (178.1 ± 2.5 cm, 81.8 ± 3.3 kg, 27.4 ± 2.0 yr) trained for 9 wk on a cycle ergometer 5 times/wk for 1 h at 75%V˙o 2 peak. The power output that elicited 66.0 ± 1.1% ofV˙o 2 peak pretraining elicited 54.0 ± 1.7% posttraining. Rest and exercise arterial glucose concentrations were similar before and after training, regardless of exercise intensity. Arterial lactate concentration during exercise was significantly greater than at rest before and after training. Compared with 65% pretraining, arterial lactate concentration decreased at ABT (4.75 ± 0.4 mM, 65% pretraining; 2.78 ± 0.3 mM, ABT) and RLT (3.76 ± 0.46 mM) ( P < 0.05). At rest after training, the percentage of glucose rate of appearance (Ra) from GNG more than doubled (1.98 ± 0.5% pretraining; 5.45 ± 1.3% posttraining), as did the rate of GNG (0.11 ± 0.03 mg ⋅ kg− 1 ⋅ min− 1pretraining, 0.24 ± 0.06 mg ⋅ kg− 1 ⋅ min− 1posttraining). During exercise after training, %glucose Rafrom GNG increased significantly at ABT (2.3 ± 0.8% at 65% pre- vs. 7.6 ± 2.1% posttraining) and RLT (6.1 ± 1.5%), whereas GNG increased almost threefold ( P < 0.05) at ABT (0.24 ± 0.08 mg ⋅ kg− 1 ⋅ min− 165% pre-, and 0.71 ± 0.18 mg ⋅ kg− 1 ⋅ min− 1posttraining) and RLT (0.75 ± 0.26 mg ⋅ kg− 1 ⋅ min− 1). We conclude that endurance training increases gluconeogenesis twofold at rest and threefold during exercise at given absolute and relative exercise intensities.

Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating

2005 ◽  
Vol 99 (1) ◽  
pp. 237-243 ◽  
Author(s):  
Takashi Ichinose ◽  
Kazunobu Okazaki ◽  
Shizue Masuki ◽  
Hiroyuki Mitono ◽  
Mian Chen ◽  
...  
Keyword(s):  
Endurance Training ◽  
Exercise Intensity ◽  
Plasma Osmolality ◽  
Young Male ◽  
Cycle Ergometer ◽  
Peak Oxygen Consumption ◽  
Cutaneous Vasodilation ◽  
Thermoregulatory Responses ◽  
Before And After ◽  
The Individual

It is well known that hyperosmolality suppresses thermoregulatory responses and that plasma osmolality (Posmol) increases with exercise intensity. We examined whether the decreased esophageal temperature thresholds for cutaneous vasodilation (THFVC) and sweating (THSR) after 10-day endurance training (ET) are caused by either attenuated increase in Posmol at a given exercise intensity or blunted sensitivity of hyperosmotic suppression. Nine young male volunteers exercised on a cycle ergometer at 60% peak oxygen consumption rate (V̇o2 peak) for 1 h/day for 10 days at 30°C. Before and after ET, thermoregulatory responses were measured during 20-min exercise at pretraining 70% V̇o2 peak in the same environment as during ET under isoosmotic or hyperosmotic conditions. Hyperosmolality by ∼10 mosmol/kgH2O was attained by acute hypertonic saline infusion. After ET, V̇o2 peak and blood volume (BV) both increased by ∼4% ( P < 0.05), followed by a decrease in THFVC ( P < 0.05) but not by that in THSR. Although there was no significant decrease in Posmol at the thresholds after ET, the sensitivity of increase in THFVC at a given increase in Posmol [ΔTHFVC/ΔPosmol,°C·(mosmol/kgH2O)−1], determined by hypertonic infusion, was reduced to 0.021 ± 0.005 from 0.039 ± 0.004 before ET ( P < 0.05). The individual reductions in ΔTHFVC/ΔPosmol after ET were highly correlated with their increases in BV around THFVC ( r = −0.89, P < 0.005). In contrast, there was no alteration in the sensitivity of the hyperosmotic suppression of sweating after ET. Thus the downward shift of THFVC after ET was partially explained by the blunted sensitivity to hyperosmolality, which occurred in proportion to the increase in BV.

scholarly journals Plasma BCAA concentrations during exercise of varied intensities in young healthy men—the impact of endurance training

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10491
Author(s):  
Anna Gawedzka ◽  
Marcin Grandys ◽  
Krzysztof Duda ◽  
Justyna Zapart-Bukowska ◽  
Jerzy A. Zoladz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Endurance Training ◽  
Exercise Intensity ◽  
Energy Homeostasis ◽  
Lactate Concentration ◽  
Incremental Exercise ◽  
Moderate Intensity ◽  
Healthy Men ◽  
Before And After ◽  
The Impact

Background Branched-chain amino acids (BCAA) i.e., leucine (Leu), isoleucine (Ile) and valine (Val) are important amino acids, which metabolism play a role in maintaining system energy homeostasis at rest and during exercise. As recently shown lowering of circulating BCAA level improves insulin sensitivity and cardiac metabolic health. However, little is known concerning the impact of a single bout of incremental exercise and physical training on the changes in blood BCAA. The present study aimed to determine the impact of a gradually increasing exercise intensity—up to maximal oxygen uptake (VO2max) on the changes of the plasma BCAA [∑BCAA]pl, before and after 5-weeks of moderate-intensity endurance training (ET). Methods Ten healthy young, untrained men performed an incremental cycling exercise test up to exhaustion to reach VO2max, before and after ET. Results We have found that exercise of low-to-moderate intensity (up to ∼50% of VO2max lasting about 12 min) had no significant effect on the [∑BCAA]pl, however the exercise of higher intensity (above 70% of VO2max lasting about 10 min) resulted in a pronounced decrease (p < 0.05) in [∑BCAA]pl. The lowering of plasma BCAA when performing exercise of higher intensity was preceded by a significant increase in plasma lactate concentration, showing that a significant attenuation of BCAA during incremental exercise coincides with exercise-induced acceleration of glycogen utilization. In addition, endurance training, which significantly increased power generating capabilities at VO2max (p = 0.004) had no significant impact on the changes of [∑BCAA]pl during this incremental exercise. Conclusion We have concluded that an exercise of moderate intensity of relatively short duration generally has no effect on the [∑BCAA]pl in young, healthy men, whereas significant decrease in [∑BCAA]pl occurs when performing exercise in heavy-intensity domain. The impact of exercise intensity on the plasma BCAA concentration seems to be especially important for patients with cardiometabolic risk undertaken cardiac rehabilitation or recreational activity.

Role of the carotid body in hyperpnea of moderate exercise in goats

1982 ◽  
Vol 52 (5) ◽  
pp. 1216-1222 ◽  
Author(s):  
G. E. Bisgard ◽  
H. V. Forster ◽  
J. Mesina ◽  
R. G. Sarazin
Keyword(s):  
Metabolic Rate ◽  
Carotid Body ◽  
Blood Gases ◽  
Co2 Production ◽  
Sham Operation ◽  
Positive Interaction ◽  
Arterial Blood ◽  
Before And After ◽  
Response To Exercise ◽  
Rest And Exercise

In the present study the ventilatory response to exercise was measured in goats before and after carotid body excision (CBE) (n = 7) or sham operation (n = 1). Nine-minute periods of moderate treadmill walking were carried out under three conditions: 4.8 kph, 0% grade during normoxia and hypoxia (arterial O2 tension approximately 43 Torr) and 4.8 kph, 5% grade during normoxia. Ventilatory variables, metabolic rate, and arterial blood acid-base and blood gases were measured at 30-s intervals for the first 3 min and again during the 6th and 9th min of exercise. In normal goats during exercise in normoxia, ventilation changed in proportion to changes in metabolic rate resulting in arterial CO2 tension (PaCO2) and arterial pH (pHa) homeostasis throughout exercise. CBE resulted in nearly equivalent hypoventilation during steady-state rest and exercise (delta PaCO2 approximately equal to 5--7 Torr) during normoxia and loss of the positive interaction between hypoxia and exercise. There was also a significant disruption of PaCO2-pHa homeostasis during the first 30 s of exercise after CBE when PaCO2 was 3 Torr below rest and pHa was 0.03 units above rest. Our data indicate: 1) that the carotid chemoreceptors may contribute a similar proportional drive to breathe during rest and exercise; 2) that transient hyperventilation at the onset of exercise after CBE may indicate an important neural drive to breathe that is normally damped by intact peripheral chemoreceptors; and 3) that the mechanism linking ventilation to CO2 production remains intact after CBE.

Artifact removal from neurophysiological signals: impact on intracranial and arterial pressure monitoring in traumatic brain injury

2020 ◽  
Vol 132 (6) ◽  
pp. 1952-1960 ◽  
Author(s):  
Seung-Bo Lee ◽  
Hakseung Kim ◽  
Young-Tak Kim ◽  
Frederick A. Zeiler ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Neurological Status ◽  
Cerebrovascular Reactivity ◽  
Cerebral Hypoperfusion ◽  
Clinical Parameters ◽  
Artifact Removal ◽  
Clinical Events ◽  
Arterial Blood ◽  
Before And After

OBJECTIVEMonitoring intracranial and arterial blood pressure (ICP and ABP, respectively) provides crucial information regarding the neurological status of patients with traumatic brain injury (TBI). However, these signals are often heavily affected by artifacts, which may significantly reduce the reliability of the clinical determinations derived from the signals. The goal of this work was to eliminate signal artifacts from continuous ICP and ABP monitoring via deep learning techniques and to assess the changes in the prognostic capacities of clinical parameters after artifact elimination.METHODSThe first 24 hours of monitoring ICP and ABP in a total of 309 patients with TBI was retrospectively analyzed. An artifact elimination model for ICP and ABP was constructed via a stacked convolutional autoencoder (SCAE) and convolutional neural network (CNN) with 10-fold cross-validation tests. The prevalence and prognostic capacity of ICP- and ABP-related clinical events were compared before and after artifact elimination.RESULTSThe proposed SCAE-CNN model exhibited reliable accuracy in eliminating ABP and ICP artifacts (net prediction rates of 97% and 94%, respectively). The prevalence of ICP- and ABP-related clinical events (i.e., systemic hypotension, intracranial hypertension, cerebral hypoperfusion, and poor cerebrovascular reactivity) all decreased significantly after artifact removal.CONCLUSIONSThe SCAE-CNN model can be reliably used to eliminate artifacts, which significantly improves the reliability and efficacy of ICP- and ABP-derived clinical parameters for prognostic determinations after TBI.

The effect of mask use on maternal oxygen saturation in term pregnancies during the COVID-19 process

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Erzat Toprak ◽  
Ayça Nazlı Bulut
Keyword(s):  
Oxygen Saturation ◽  
Pregnant Women ◽  
Stress Test ◽  
Statistical Significance ◽  
Categorical Variables ◽  
Fisher Exact Test ◽  
Coin Toss ◽  
Arterial Blood ◽  
Surgical Masks ◽  
Before And After

AbstractObjectivesOur aim was to evaluate the effect of standard surgical and N-95 respiratory mask use on maternal oxygen saturation, vital signs and result on non-stress tests in term pregnancies.MethodsIt is a prospective observational study. The study included healthy, not in labor, singleton pregnant women of 370/7–410/7 weeks who were applied to our hospital for routine obstetric control examination between March 1, 2020, and August 31, 2020. Patients were randomised by coin toss method. Oxygen saturation, systolic, and diastolic arterial blood pressure, pulse, respiratory rate, and temperature of pregnant women using surgical masks and respiratory masks were measured before and after the non-stress test. The tolerance of the masks was also evaluated. Student’s t-test was used for variables showing parametric distribution and the Mann Whitney U-test was used for non-parametric tests. The categorical variables between the groups was analyzed by using the Chi square test or Fisher Exact test. The statistical significance level was taken as p<0.05 in all tests.ResultsA total of 297 pregnant women using masks were included in the study. The effect of mask type on oxygen saturation before and after the non-stress test was found to be significant (97.1±1.8 corresponds to 95.3±2.6 for the surgical mask, p=0.0001; 97.8±1.7 corresponds to 93.7±2.0 for the respiratory mask, p=0.0001). Mask tolerance of patients using respiratory masks was significantly higher than those using surgical masks (mean 8, 1–10, p=0.0001).ConclusionsSurgical mask and respiratory mask usage decreased significantly in oxygen saturation in term pregnancies.

Effects of endurance training on hyperammonaemia during a 45-min constant exercise intensity

1989 ◽  
Vol 59 (4) ◽  
pp. 268-272 ◽  
Author(s):  
C. Denis ◽  
M-T. Linossier ◽  
D. Dormois ◽  
M. Cottier-Perrin ◽  
A. Geyssant ◽  
...  
Keyword(s):  
Endurance Training ◽  
Exercise Intensity

Regulation of muscle glycogen phosphorylase activity following short-term endurance training

1996 ◽  
Vol 270 (2) ◽  
pp. E328-E335 ◽  
Author(s):  
A. Chesley ◽  
G. J. Heigenhauser ◽  
L. L. Spriet
Keyword(s):  
Endurance Training ◽  
Muscle Glycogen ◽  
Glycogen Phosphorylase ◽  
Citrate Synthase ◽  
Phosphorylase Activity ◽  
Short Term ◽  
Mitochondrial Potential ◽  
Before And After ◽  
Glycogen Phosphorylase Activity ◽  
Muscle Biopsies

The purpose of this study was to examine the regulation (hormonal, substrate, and allosteric) of muscle glycogen phosphorylase (Phos) activity and glycogenolysis after short-term endurance training. Eight untrained males completed 6 days of cycle exercise (2 h/day) at 65% of maximal O2 uptake (Vo2max). Before and after training subjects cycled for 15 min at 80% of Vo2max, and muscle biopsies and blood samples were obtained at 0 and 30 s, 7.5 and 15 min, and 0, 5, 10, and 15 min of exercise. Vo2max was unchanged with training but citrate synthase (CS) activity increased by 20%. Muscle glycogenolysis was reduced by 42% during the 15-min exercise challenge following training (198.8 +/- 36.9 vs. 115.4 +/- 25.1 mmol/kg dry muscle), and plasma epinephrine was blunted at 15 min of exercise. The Phos a mole fraction was unaffected by training. Muscle phosphocreatine utilization and free Pi and AMP accumulations were reduced with training at 7.5 and 15 min of exercise. It is concluded that posttransformational control of Phos, exerted by reductions in substrate (free Pi) and allosteric modulator (free AMP) contents, is responsible for a blunted muscle glycogenolysis after 6 days of endurance training. The increase in CS activity suggests that the reduction of muscle glycogenolysis was due in part to an enhanced mitochondrial potential.

Effects of Increased Central Cholinergic Activity on the Metabolic Challenge Induced by Submaximal Exercise in Rats: Adrenomedullary Secretion Influences

Pharmacology ◽  
2021 ◽  
pp. 1-8
Author(s):  
Alex Guazzi Rodrigues ◽  
Helton Oliveira Campos ◽  
Lucas Rios Drummond ◽  
Umeko Marubayashi ◽  
Cândido Celso Coimbra
Keyword(s):  
Plasma Glucose ◽  
Sham Group ◽  
Plasma Concentrations ◽  
Submaximal Exercise ◽  
Cholinergic Activity ◽  
Running Exercise ◽  
Cholinergic Pathway ◽  
Before And After ◽  
Metabolic Challenge ◽  
Rest And Exercise

<b><i>Aim:</i></b> The aim of this study was to assess the influence of adrenomedullary secretion on the plasma glucose, lactate, and free fatty acids (FFAs) during running exercise in rats submitted to intracerebroventricular (i.c.v.) injection of physostigmine (PHY). PHY i.c.v. was used to activate the central cholinergic system. <b><i>Methods:</i></b> Wistar rats were divided into sham-saline (sham-SAL), sham-PHY, adrenal medullectomy-SAL, and ADM-PHY groups. The plasma concentrations of glucose, lactate, and FFAs were determined immediately before and after i.c.v. injection of 20 μL of SAL or PHY at rest and during running exercise on a treadmill. <b><i>Results:</i></b> The i.c.v. injection of PHY at rest increased plasma glucose in the sham group, but not in the ADM group. An increase in plasma glucose, lactate, and FFAs mobilization from adipose tissue was observed during physical exercise in the sham-SAL group; however, the increase in plasma glucose was greater with i.c.v. PHY. Moreover, the hyperglycemia induced by exercise and PHY in the ADM group were blunted by ADM, whereas FFA mobilization was unaffected. <b><i>Conclusion:</i></b> These results indicate that there is a dual metabolic control by which activation of the central cholinergic pathway increases plasma glucose but not FFA during rest and exercise, and that this hyperglycemic response is dependent on adrenomedullary secretion.

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