Exogenous ketosis impacts neither performance nor muscle glycogen breakdown in prolonged endurance exercise

Exogenous ketosis produced by oral ketone ester ingestion during the early phase of prolonged endurance exercise and against the background of adequate carbohydrate intake neither causes muscle glycogen sparing nor improves performance in the final stage of the event. However, such exogenous ketosis may decrease buffering capacity in the approach of the final episode of the event. Furthermore, ketone ester intake during exercise may reduce appetite immediately after exercise.

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Faculty Opinions recommendation of Exogenous ketosis impacts neither performance nor muscle glycogen breakdown in prolonged endurance exercise.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.737953805.793575362 ◽

2020 ◽

Author(s):

Brendan Egan

Keyword(s):

Endurance Exercise ◽

Muscle Glycogen ◽

Glycogen Breakdown

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Fiber type-specific muscle glycogen sparing due to carbohydrate intake before and during exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.00799.2006 ◽

2007 ◽

Vol 102 (1) ◽

pp. 183-188 ◽

Cited By ~ 27

Author(s):

K. De Bock ◽

W. Derave ◽

M. Ramaekers ◽

E. A. Richter ◽

P. Hespel

Keyword(s):

Muscle Glycogen ◽

Glycogen Content ◽

Fiber Type ◽

Vastus Lateralis ◽

Periodic Acid ◽

Carbohydrate Intake ◽

Vastus Lateralis Muscle ◽

Type I ◽

Type I Fibers ◽

Glycogen Sparing

The effect of carbohydrate intake before and during exercise on muscle glycogen content was investigated. According to a randomized crossover study design, eight young healthy volunteers ( n = 8) participated in two experimental sessions with an interval of 3 wk. In each session subjects performed 2 h of constant-load bicycle exercise (∼75% maximal oxygen uptake). On one occasion (CHO), they received carbohydrates before (∼150 g) and during (1 g·kg body weight−1·h−1) exercise. On the other occasion they exercised after an overnight fast (F). Fiber type-specific relative glycogen content was determined by periodic acid Schiff staining combined with immunofluorescence in needle biopsies from the vastus lateralis muscle before and immediately after exercise. Preexercise glycogen content was higher in type IIa fibers [9.1 ± 1 × 10−2 optical density (OD)/μm2] than in type I fibers (8.0 ± 1 × 10−2 OD/μm2; P < 0.0001). Type IIa fiber glycogen content decreased during F from 9.6 ± 1 × 10−2 OD/μm2 to 4.5 ± 1 × 10−2 OD/μm2 ( P = 0.001), but it did not significantly change during CHO ( P = 0.29). Conversely, in type I fibers during CHO and F the exercise bout decreased glycogen content to the same degree. We conclude that the combination of carbohydrate intake both before and during moderate- to high-intensity endurance exercise results in glycogen sparing in type IIa muscle fibers.

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Regulation of muscle glycogenolytic flux during intense aerobic exercise after caffeine ingestion

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1998.275.2.r596 ◽

1998 ◽

Vol 275 (2) ◽

pp. R596-R603 ◽

Cited By ~ 18

Author(s):

Alan Chesley ◽

Richard A. Howlett ◽

George J. F. Heigenhauser ◽

Eric Hultman ◽

Lawrence L. Spriet

Keyword(s):

Aerobic Exercise ◽

Muscle Glycogen ◽

Glycogen Phosphorylase ◽

Vastus Lateralis ◽

Energy Status ◽

Caffeine Ingestion ◽

Sparing Effect ◽

Muscle Biopsies ◽

Glycogen Sparing ◽

Epinephrine Concentration

This study examined the effects of caffeine (Caf) ingestion on muscle glycogen use and the regulation of muscle glycogen phosphorylase (Phos) activity during intense aerobic exercise. In two separate trials, 12 untrained males ingested either placebo (Pl) or Caf (9 mg/kg body wt) 1 h before cycling at 80% maximum O2 consumption (V˙o 2 max) for 15 min. Muscle biopsies were obtained from the vastus lateralis at 0, 3, and 15 min of exercise. In this study, glycogen “sparing” was defined as a 10% or greater reduction in muscle glycogen use during exercise after Caf ingestion compared with Pl. Muscle glycogen use decreased by 28% (Pl 255 ± 38 vs. Caf 184 ± 24 mmol/kg dry muscle) after Caf in six subjects [glycogen sparers (Sp)] but was unaffected by Caf in six other subjects [nonsparers (NSp), Pl 210 ± 35 vs. Caf 214 ± 37 mmol/kg dry muscle]. In both groups, Caf significantly increased resting free fatty acid concentration, significantly increased epinephrine concentration by twofold during exercise, and increased the Phos a mole fraction at 3 min of exercise compared with Pl, although not significantly. Caf improved the energy status of the muscle during exercise in the Sp group: muscle phosphocreatine (PCr) degradation was significantly reduced (Pl 47.9 ± 3.6 vs. Caf 40.4 ± 6.7 mmol/kg dry muscle at 3 min) and the accumulations of free ADP and free AMP (Pl 6.8 ± 1.3 vs. Caf 3.1 ± 1.4 μmol/kg dry muscle at 3 min; Pl 8.7 ± 0.8 vs. Caf 4.7 ± 1.1 μmol/kg dry muscle at 15 min) were significantly reduced. Caf had no effect on these measurements in the NSp group. It is concluded that the Caf-induced decrease in flux through Phos (glycogen-sparing effect) is mediated via an improved energy status of the muscle in the early stages of intense aerobic exercise. This may be related to an increased availability of fat and/or ability of mitochondria to oxidize fat during exercise preceded by Caf ingestion. It is presently unknown why the glycogen-sparing effect of Caf does not occur in all untrained individuals during intense aerobic exercise.

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A Ketone Ester Drink Enhances Endurance Exercise Performance in Parkinson’s Disease

Frontiers in Neuroscience ◽

10.3389/fnins.2020.584130 ◽

2020 ◽

Vol 14 ◽

Cited By ~ 1

Author(s):

Nicholas G. Norwitz ◽

David J. Dearlove ◽

Meng Lu ◽

Kieran Clarke ◽

Helen Dawes ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Endurance Exercise ◽

Exercise Performance ◽

Ketone Ester

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Effect of endurance exercise training on muscle glycogen supercompensation in rats

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.2.711 ◽

1997 ◽

Vol 82 (2) ◽

pp. 711-715 ◽

Cited By ~ 61

Author(s):

Akira Nakatani ◽

Dong-Ho Han ◽

Polly A. Hansen ◽

Lorraine A. Nolte ◽

Helen H. Host ◽

...

Keyword(s):

Exercise Training ◽

Endurance Exercise ◽

Muscle Glycogen ◽

Glucose Transporter ◽

Glycogen Synthase ◽

Recovery Period ◽

Chow Diet ◽

Glycogen Accumulation ◽

Transporter Protein ◽

Endurance Exercise Training

Nakatani, Akira, Dong-Ho Han, Polly A. Hansen, Lorraine A. Nolte, Helen H. Host, Robert C. Hickner, and John O. Holloszy.Effect of endurance exercise training on muscle glycogen supercompensation in rats. J. Appl. Physiol. 82(2): 711–715, 1997.—The purpose of this study was to test the hypothesis that the rate and extent of glycogen supercompensation in skeletal muscle are increased by endurance exercise training. Rats were trained by using a 5-wk-long swimming program in which the duration of swimming was gradually increased to 6 h/day over 3 wk and then maintained at 6 h/day for an additional 2 wk. Glycogen repletion was measured in trained and untrained rats after a glycogen-depleting bout of exercise. The rats were given a rodent chow diet plus 5% sucrose in their drinking water ad libitum during the recovery period. There were remarkable differences in both the rates of glycogen accumulation and the glycogen concentrations attained in the two groups. The concentration of glycogen in epitrochlearis muscle averaged 13.1 ± 0.9 mg/g wet wt in the untrained group and 31.7 ± 2.7 mg/g in the trained group ( P < 0.001) 24 h after the exercise. This difference could not be explained by a training effect on glycogen synthase. The training induced ∼50% increases in muscle GLUT-4 glucose transporter protein and in hexokinase activity in epitrochlearis muscles. We conclude that endurance exercise training results in increases in both the rate and magnitude of muscle glycogen supercompensation in rats.

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Mechanism linking glycogen concentration and glycogenolytic rate in perfused contracting rat skeletal muscle

Biochemical Journal ◽

10.1042/bj2840777 ◽

1992 ◽

Vol 284 (3) ◽

pp. 777-780 ◽

Cited By ~ 46

Author(s):

P Hespel ◽

E A Richter

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Rat Skeletal Muscle ◽

Phosphorylase Activity ◽

Tension Development ◽

Glycogen Concentration ◽

The Difference ◽

Resting Muscle ◽

Muscle Glycogen Concentration ◽

Glycogen Breakdown

The influence of differences in glycogen concentration on glycogen breakdown and on phosphorylase activity was investigated in perfused contracting rat skeletal muscle. The rats were preconditioned by a combination of swimming exercise and diet (carbohydrate-free or carbohydrate-rich) in order to obtain four sub-groups of rats with varying resting muscle glycogen concentrations (range 10-60 mumol/g wet wt.). Pre-contraction muscle glycogen concentration was closely positively correlated with glycogen breakdown over 15 min of intermittent short tetanic contractions (r = 0.75; P less than 0.001; n = 56) at the same tension development and oxygen uptake. Additional studies in supercompensated and glycogen-depleted hindquarters during electrical stimulation for 20 s or 2 min revealed that the difference in glycogenolytic rate was found at the beginning rather than at the end of the contraction period. Phosphorylase alpha activity was approximately twice as high (P less than 0.001) in supercompensated muscles as in glycogen-depleted muscles after 20 s as well as after 2 min of contractions. It is concluded that glycogen concentration is an important determinant of phosphorylase activity in contracting skeletal muscle, and probably via this mechanism a regulator of glycogenolytic rate during muscle contraction.

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Adaptations of skeletal muscle to endurance exercise and their metabolic consequences

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.4.831 ◽

1984 ◽

Vol 56 (4) ◽

pp. 831-838 ◽

Cited By ~ 1018

Author(s):

J. O. Holloszy ◽

E. F. Coyle

Keyword(s):

Skeletal Muscle ◽

Blood Glucose ◽

Exercise Training ◽

Endurance Exercise ◽

Muscle Glycogen ◽

Lactate Production ◽

Strenuous Exercise ◽

Mitochondrial Content ◽

Respiratory Capacity ◽

Endurance Exercise Training

Regularly performed endurance exercise induces major adaptations in skeletal muscle. These include increases in the mitochondrial content and respiratory capacity of the muscle fibers. As a consequence of the increase in mitochondria, exercise of the same intensity results in a disturbance in homeostasis that is smaller in trained than in untrained muscles. The major metabolic consequences of the adaptations of muscle to endurance exercise are a slower utilization of muscle glycogen and blood glucose, a greater reliance on fat oxidation, and less lactate production during exercise of a given intensity. These adaptations play an important role in the large increase in the ability to perform prolonged strenuous exercise that occurs in response to endurance exercise training.

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