scholarly journals CARBOHYDRATE INGESTION DURING RUNNING AND MUSCLE GLYCOGEN UTILIZATION IN FED HUMANS

1995 ◽  
Vol 27 (Supplement) ◽  
pp. S206
Author(s):  
C. Chryssanthopoulos ◽  
C. Williams ◽  
A. Nowitz
Keyword(s):  
Muscle Glycogen ◽  
Carbohydrate Ingestion ◽  
Glycogen Utilization

Effect of carbohydrate ingestion on exercise metabolism

1988 ◽  
Vol 65 (4) ◽  
pp. 1553-1555 ◽  
Author(s):  
M. Hargreaves ◽  
C. A. Briggs
Keyword(s):  
Muscle Glycogen ◽  
Venous Blood ◽  
Cycle Ergometer ◽  
Strenuous Exercise ◽  
Carbohydrate Ingestion ◽  
Ergometer Exercise ◽  
Glucose Polymer ◽  
Before And After ◽  
Plasma Insulin Levels ◽  
Glycogen Utilization

Five male cyclists were studied during 2 h of cycle ergometer exercise (70% VO2 max) on two occasions to examine the effect of carbohydrate ingestion on muscle glycogen utilization. In the experimental trial (CHO) subjects ingested 250 ml of a glucose polymer solution containing 30 g of carbohydrate at 0, 30, 60, and 90 min of exercise; in the control trial (CON) they received an equal volume of a sweet placebo. No differences between trials were seen in O2 uptake or heart rate during exercise. Venous blood glucose was similar before exercise in both trials, but, on average, was higher during exercise in CHO [5.2 +/- 0.2 (SE) mmol/l] compared with CON (4.8 +/- 0.1, P less than 0.05). Plasma insulin levels were similar in both trials. Muscle glycogen levels were also similar in CHO and CON both before and after exercise; accordingly, there was no difference between trials in the amount of glycogen used during the 2 h of exercise (CHO = 62.8 +/- 10.1 mmol/kg wet wt, CON = 56.9 +/- 10.1). The results of this study indicate that carbohydrate ingestion does not influence the utilization of muscle glycogen during prolonged strenuous exercise.

Effect of carbohydrate ingestion on metabolism during running and cycling

2001 ◽  
Vol 91 (5) ◽  
pp. 2125-2134 ◽  
Author(s):  
Melissa J. Arkinstall ◽  
Clinton R. Bruce ◽  
Vasilis Nikolopoulos ◽  
Andrew P. Garnham ◽  
John A. Hawley
Keyword(s):  
Body Mass ◽  
Plasma Glucose ◽  
Muscle Glycogen ◽  
Lactate Threshold ◽  
Glucose Oxidation ◽  
Dry Mass ◽  
Carbohydrate Oxidation ◽  
Total Carbohydrate ◽  
Carbohydrate Ingestion ◽  
Glycogen Utilization

The effects of carbohydrate or water ingestion on metabolism were investigated in seven male subjects during two running and two cycling trials lasting 60 min at individual lactate threshold using indirect calorimetry, U-14C-labeled tracer-derived measures of the rates of oxidation of plasma glucose, and direct determination of mixed muscle glycogen content from the vastus lateralis before and after exercise. Subjects ingested 8 ml/kg body mass of either a 6.4% carbohydrate-electrolyte solution (CHO) or water 10 min before exercise and an additional 2 ml/kg body mass of the same fluid after 20 and 40 min of exercise. Plasma glucose oxidation was greater with CHO than with water during both running (65 ± 20 vs. 42 ± 16 g/h; P < 0.01) and cycling (57 ± 16 vs. 35 ± 12 g/h; P < 0.01). Accordingly, the contribution from plasma glucose oxidation to total carbohydrate oxidation was greater during both running (33 ± 4 vs. 23 ± 3%; P < 0.01) and cycling (36 ± 5 vs. 22 ± 3%; P < 0.01) with CHO ingestion. However, muscle glycogen utilization was not reduced by the ingestion of CHO compared with water during either running (112 ± 32 vs. 141 ± 34 mmol/kg dry mass) or cycling (227 ± 36 vs. 216 ± 39 mmol/kg dry mass). We conclude that, compared with water, 1) the ingestion of carbohydrate during running and cycling enhanced the contribution of plasma glucose oxidation to total carbohydrate oxidation but 2) did not attenuate mixed muscle glycogen utilization during 1 h of continuous submaximal exercise at individual lactate threshold.

Frequent Carbohydrate Ingestion Reduces Muscle Glycogen Depletion and Postpones Fatigue Relative to a Single Bolus

2020 ◽  
Vol 30 (3) ◽  
pp. 203-209
Author(s):  
Campbell Menzies ◽  
Michael Wood ◽  
Joel Thomas ◽  
Aaron Hengist ◽  
Jean-Philippe Walhin ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Muscle Glycogen ◽  
Metabolic Response ◽  
Treadmill Running ◽  
Utilization Rate ◽  
Glycogen Depletion ◽  
Carbohydrate Ingestion ◽  
Single Bolus ◽  
Significant Difference ◽  
Glycogen Utilization

The timing of carbohydrate ingestion and how this influences net muscle glycogen utilization and fatigue has only been investigated in prolonged cycling. Past findings may not translate to running because each exercise mode is distinct both in the metabolic response to carbohydrate ingestion and in the practicalities of carbohydrate ingestion. To this end, a randomized, cross-over design was employed to contrast ingestion of the same sucrose dose either at frequent intervals (15 × 5 g every 5 min) or at a late bolus (1 × 75 g after 75 min) during prolonged treadmill running to exhaustion in six well-trained runners ( 61 ± 4 ml·kg−1·min−1). The muscle glycogen utilization rate was lower in every participant over the first 75 min of running (Δ 0.51 mmol·kg dm−1·min−1; 95% confidence interval [−0.02, 1.04] mmol·kg dm−1·min−1) and, subsequently, all were able to run for longer when carbohydrate had been ingested frequently from the start of exercise compared with when carbohydrate was ingested as a single bolus toward the end of exercise (105.6 ± 3.0 vs. 96.4 ± 5.0 min, respectively; Δ 9.3 min, 95% confidence interval [2.8, 15.8] min). A moderate positive correlation was apparent between the magnitude of glycogen sparing over the first 75 min and the improvement in running capacity (r = .58), with no significant difference in muscle glycogen concentrations at the point of exhaustion. This study indicates that failure to ingest carbohydrates from the outset of prolonged running increases reliance on limited endogenous muscle glycogen stores—the ergolytic effects of which cannot be rectified by subsequent carbohydrate ingestion late in exercise.

Influence of carbohydrate ingestion on fuel substrate turnover and oxidation during prolonged exercise

1994 ◽  
Vol 76 (6) ◽  
pp. 2364-2372 ◽  
Author(s):  
A. N. Bosch ◽  
S. C. Dennis ◽  
T. D. Noakes
Keyword(s):  
Blood Glucose ◽  
Muscle Glycogen ◽  
Glucose Oxidation ◽  
Prolonged Exercise ◽  
Fat Free Mass ◽  
O2 Uptake ◽  
Carbohydrate Ingestion ◽  
Glycogen Utilization

This study examined effects of ingesting a 10% carbohydrate (CHO) drink (CI) or placebo (PI) at 500 ml/h on total (splanchnic) glucose appearance (endogenous+exogenous; Ra), blood glucose oxidation, and muscle glycogen utilization in 14 male endurance-trained cyclists who rode for 180 min at 70% of maximal O2 uptake after CHO loading [starting muscle glycogen 203 +/- 7 (SE) mmol/kg wet wt]. Total CHO oxidation was similar in CI and PI, but Ra increased significantly during the trial in both groups with CI reaching a plateau after 75 min. Ra was significantly greater in CI than in PI at the end of exercise. Blood glucose oxidation also increased significantly during the trial to a plateau in CI and was significantly higher in CI than in PI at the end of exercise. However, mean endogenous Ra was significantly lower in CI than in PI throughout exercise, as was oxidation of endogenous blood glucose, which remained almost constant in CI and reached 43 +/- 8 and 73 +/- 13 mumol.min-1.kg fat-free mass-1 in CI and PI, respectively, at the end of exercise. At 0.83 g/min of CHO ingestion, 0.77 +/- 0.03 g/min was oxidized. Muscle glycogen utilization was identical in both groups and was higher during the 1st h of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Augmented muscle glycogen utilization following a single session of sprint training in hypoxia

2021 ◽  
Author(s):  
Nobukazu Kasai ◽  
Fumiya Tanji ◽  
Aya Ishibashi ◽  
Hayato Ohnuma ◽  
Hideyuki Takahashi ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Sprint Training ◽  
Single Session ◽  
Glycogen Utilization

Effect of fat emulsion infusion and fat feeding on muscle glycogen utilization during cycle exercise

1993 ◽  
Vol 75 (4) ◽  
pp. 1513-1518 ◽  
Author(s):  
M. D. Vukovich ◽  
D. L. Costill ◽  
M. S. Hickey ◽  
S. W. Trappe ◽  
K. J. Cole ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Muscle Glycogen ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Serum Triglyceride ◽  
Cycle Ergometer ◽  
Fat Emulsion ◽  
Cycle Exercise ◽  
Glycogen Utilization ◽  
Fat Feeding

Elevated plasma fatty acids have been shown to spare muscle glycogen during exercise. However, on the basis of recent findings, the saturation of fatty acids may influence this response. The purpose of this study was to determine whether saturated or unsaturated fatty acids affected muscle glycogenolysis to varying degrees during cycle exercise. Five healthy men completed three 60-min cycle ergometer trials (EX) at approximately 70% maximal O2 uptake (VO2max). Triglyceride levels were elevated by a fat feeding (FF) composed of 90% saturated fatty acids (heavy whipping cream, 90 g) or by the infusion of Intralipid (IL; Clintec Nutrition; 45 ml/h of 20% IL, 9.0 g), which was 85% unsaturated. A control trial (CON) consisted of a light breakfast (43 g carbohydrate and 1 g fat). Heparin (2,000 U) was administered 15 min before EX in FF and IL trials, resulting in one- and threefold increases in free fatty acid (FFA) levels in IL and FF, respectively. Pre-EX muscle glycogen did not differ. The utilization of muscle glycogen during 60 min of EX was less (P < 0.05) during the FF (60.0 +/- 5.2 mmol/kg wet wt) and IL (58.6 +/- 6.2 mmol/kg wet wt) compared with CON (81.8 +/- 7.5 mmol/kg wet wt). There was no difference between FF and IL in the amount of glycogen utilized. Serum triglyceride levels were greater (P < 0.05) at preheparin in FF (1.58 +/- 0.37 mmol/l) and IL (0.98 +/- 0.13 mmol/l) compared with CON (0.47 +/- 0.14 mmol/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Substrate utilization in leg muscle of men after heat acclimation

1987 ◽  
Vol 63 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. P. Kirwan ◽  
D. L. Costill ◽  
H. Kuipers ◽  
M. J. Burrell ◽  
W. J. Fink ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Glycogen ◽  
Respiratory Exchange Ratio ◽  
Plasma Free Fatty Acid ◽  
Heat Acclimation ◽  
Substrate Utilization ◽  
Acclimation Period ◽  
Glycogen Utilization ◽  
Leg Muscle ◽  
Increased Blood Flow

Eight men were heat acclimated (39.6 degrees C and 29.2% rh) for 8 days to examine changes in substrate utilization. A heat exercise test (HET), (cycling for 60 min; 50% maximal O2 consumption) was performed before (UN-HET) and after (ACC-HET) the acclimation period. Muscle glycogen utilization (67.0 vs. 37.6 mmol/kg wet wt), respiratory exchange ratio (0.85 +/- 0.002 vs. 0.83 +/- 0.001), and calculated rate of carbohydrate oxidation (75.15 +/- 1.38 vs. 64.80 +/- 1.52 g/h) were significantly reduced (P less than 0.05) during the ACC-HET. Significantly lower (P less than 0.05) femoral venous glucose (15, 30, and 45 min) and lactate (15 min) levels were observed during the ACC-HET. No differences were observed in plasma free fatty acid (FFA) and glycerol concentrations or glucose, lactate and glycerol arteriovenous uptake/release between tests. A small but significant increase (P less than 0.05) above resting levels in FFA uptake was observed during the ACC-HET. Leg blood flow was slightly greater (P greater than 0.05) during the ACC-HET (4.64 +/- 0.13 vs. 4.80 +/- 0.13 l/min). These findings indicate a reduced use of muscle glycogen following heat acclimation. However, the decrease is not completely explained by a shift toward greater lipid oxidation or increased blood flow.

Epinephrine inhibits exogenous glucose utilization in exercising horses

2000 ◽  
Vol 88 (5) ◽  
pp. 1777-1790 ◽  
Author(s):  
Raymond J. Geor ◽  
Kenneth W. Hinchcliff ◽  
Laura Jill McCutcheon ◽  
Richard A. Sams
Keyword(s):  
Muscle Glycogen ◽  
Glucose Utilization ◽  
Treadmill Exercise ◽  
Moderate Intensity ◽  
Oral Glucose ◽  
Moderate Intensity Exercise ◽  
Epinephrine Infusion ◽  
Glucose Administration ◽  
Exogenous Glucose ◽  
Glycogen Utilization

This study examined the effects of preexercise glucose administration, with and without epinephrine infusion, on carbohydrate metabolism in horses during exercise. Six horses completed 60 min of treadmill exercise at 55 ± 1% maximum O2 uptake 1) 1 h after oral administration of glucose (2 g/kg; G trial); 2) 1 h after oral glucose and with an intravenous infusion of epinephrine (0.2 μmol ⋅ kg− 1 ⋅ min− 1; GE trial) during exercise, and 3) 1 h after water only (F trial). Glucose administration (G and GE) caused hyperinsulinemia and hyperglycemia (∼8 mM). In GE, plasma epinephrine concentrations were three- to fourfold higher than in the other trials. Compared with F, the glucose rate of appearance was ∼50% and ∼33% higher in G and GE, respectively, during exercise. The glucose rate of disappearance was ∼100% higher in G than in F, but epinephrine infusion completely inhibited the increase in glucose uptake associated with glucose administration. Muscle glycogen utilization was higher in GE [349 ± 44 mmol/kg dry muscle (dm)] than in F (218 ± 28 mmol/kg dm) and G (201 ± 35 mmol/kg dm). We conclude that 1) preexercise glucose augments utilization of plasma glucose in horses during moderate-intensity exercise but does not alter muscle glycogen usage and 2) increased circulating epinephrine inhibits the increase in glucose rate of disappearance associated with preexercise glucose administration and increases reliance on muscle glycogen for energy transduction.

Effect of carbohydrate feedings on muscle glycogen utilization and exercise performance

1984 ◽  
Vol 16 (3) ◽  
pp. 219???222 ◽  
Author(s):  
M. HARGREAVES ◽  
D. L. COSTILL ◽  
A. COGGAN ◽  
W. J. FINK ◽  
I. NISHIBATA
Keyword(s):  
Muscle Glycogen ◽  
Exercise Performance ◽  
Glycogen Utilization
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