Effect of glycogen depletion on the ventilatory response to exercise

1983 ◽  
Vol 54 (2) ◽  
pp. 470-474 ◽  
Author(s):  
G. J. Heigenhauser ◽  
J. R. Sutton ◽  
N. L. Jones
Keyword(s):  
Muscle Glycogen ◽  
Power Output ◽  
Co2 Flux ◽  
Glycogen Depletion ◽  
Experimental Conditions ◽  
Co2 Output ◽  
Partial Pressures ◽  
End Tidal ◽  
Response To Exercise ◽  
Male Subjects

Five male subjects performed two graded exercise studies, one during control conditions and the other after reduction of muscle glycogen content by repeated maximum exercise and a high fat-protein diet. Reduction in preexercise muscle glycogen from 59.1 to 17.1 mumol X g-1 (n = 3) was associated with a 14% reduction in maximum power output but no change in maximum O2 intake; at any given power output O2 intake, heart rate, and ventilation (VE) were significantly higher, CO2 output (VCO2) was similar, and the respiratory exchange ratio was lower during glycogen depletion compared with control. The higher VE during glycogen depletion was associated with a higher VE/VCO2 ratio, lower end-tidal and mixed venous CO2 partial pressures, and higher blood pH than in the control studies. Changes in exercise VE accompanying glycogen depletion were not explained by changes in CO2 flux to the lungs suggesting that other factors served to modulate VE in these experimental conditions.

Control of breathing at the start of exercise as influenced by posture

1983 ◽  
Vol 55 (5) ◽  
pp. 1460-1466 ◽  
Author(s):  
D. Weiler-Ravell ◽  
D. M. Cooper ◽  
B. J. Whipp ◽  
K. Wasserman
Keyword(s):  
Stroke Volume ◽  
Phase I ◽  
Ventilatory Response ◽  
Normal Subjects ◽  
Initial Increase ◽  
Base Line ◽  
Co2 Output ◽  
End Tidal ◽  
Response To Exercise ◽  
Initial Change

It has been suggested that the initial phase of the ventilatory response to exercise is governed by a mechanism which responds to the increase in pulmonary blood flow (Q)--cardiodynamic hyperpnea. Because the initial change in stroke volume and Q is less in the supine (S) than in the upright (U) position at the start of exercise, we hypothesized that the increase in ventilation would also be less in the first 20 s (phase I) of S exercise. Ten normal subjects performed cycle ergometry in the U and S positions. Inspired ventilation (VI), O2 uptake (VO2), CO2 output (VCO2), corrected for changes in lung gas stores, and end-tidal O2 and CO2 tensions were measured breath by breath. Heart rate (HR) was determined beat by beat. The phase I ventilatory response was markedly different in the two positions. In the U position, VI increased abruptly by 81 +/- 8% (mean +/- SE) above base line. In the S position, the phase I response was significantly attenuated (P less than 0.001), the increase in VI being 50 +/- 6%. Similarly, the phase I VO2 and VO2/HR responses reflecting the initial increase in Q and stroke volume, were attenuated (P less than 0.001) in the S posture, compared with that for U; VO2 increased 49 +/- 5.3 and 113 +/- 14.7% in S and U, respectively, and VO2/HR increased 16 +/- 3.0 and 76 +/- 7.1% in the S and U, respectively. The increase in VI correlated well with the increase in VO2, (r = 0.80, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle glycogen recovery after exercise during glucose and fructose intake monitored by13C-NMR

1996 ◽  
Vol 81 (4) ◽  
pp. 1495-1500 ◽  
Author(s):  
Adrianus J. Van Den Bergh ◽  
Sibrand Houtman ◽  
Arend Heerschap ◽  
Nancy J. Rehrer ◽  
Hendrikus J. Van Den Boogert ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Muscle Glycogen ◽  
Glycogen Content ◽  
Vastus Lateralis ◽  
Glycogen Depletion ◽  
Glycogen Concentration ◽  
Fructose Intake ◽  
Glycogen Stores ◽  
Male Subjects ◽  
C Nmr

Van Den Bergh, Adrianus J., Sibrand Houtman, Arend Heerschap, Nancy J. Rehrer, Hendrikus J. Van Den Boogert, Berend Oeseburg, and Maria T. E. Hopman. Muscle glycogen recovery after exercise during glucose and fructose intake monitored by13C-NMR. J. Appl. Physiol. 81(4): 1495–1500, 1996.—The purpose of this study was to examine muscle glycogen recovery with glucose feeding (GF) compared with fructose feeding (FF) during the first 8 h after partial glycogen depletion by using13C-nuclear magnetic resonance (NMR) on a clinical 1.5-T NMR system. After measurement of the glycogen concentration of the vastus lateralis (VL) muscle in seven male subjects, glycogen stores of the VL were depleted by bicycle exercise. During 8 h after completion of exercise, subjects were orally given either GF or FF while the glycogen content of the VL was monitored by13C-NMR spectroscopy every second hour. The muscular glycogen concentration was expressed as a percentage of the glycogen concentration measured before exercise. The glycogen recovery rate during GF (4.2 ± 0.2%/h) was significantly higher ( P < 0.05) compared with values during FF (2.2 ± 0.3%/h). This study shows that 1) muscle glycogen levels are perceptible by 13C-NMR spectroscopy at 1.5 T and 2) the glycogen restoration rate is higher after GF compared with after FF.

Diminished hormonal responses to exercise in trained rats

1977 ◽  
Vol 43 (6) ◽  
pp. 953-958 ◽  
Author(s):  
H. Galbo ◽  
E. A. Richter ◽  
J. J. Holst ◽  
N. J. Christensen
Keyword(s):  
Muscle Glycogen ◽  
Plasma Concentrations ◽  
Male Rats ◽  
Hepatic Glycogen ◽  
Plasma Glucagon ◽  
Glycogen Depletion ◽  
Hormonal Responses ◽  
Tissue Sensitivity ◽  
Glucagon And Insulin ◽  
Response To Exercise

Male rats (120 g) either were subjected to a 12-wk physical training program (T rats) or were sedentary controls (C rats). Subsequently the rats were killed at rest or after a 45- or 90-min forced swim. At rest, T rats had higher liver and muscle glycogen concentrations but lower plasma insulin. During exercise, blood glucose increased 60% in T rats but decreased 20% in C rats. Plasma glucagon and insulin concentrations did not change in T rats but plasma glucagon increased and insulin decreased markedly in C rats. Plasma epinephrine (90 min: range, 0.78–2.96 ng-ml-1, (T) vs. 4.42–15.67 (C)) and norepinephrine (90 min: 0.70–2.22 (T) vs. 2.50–6.10 (C)) were lower in T than in C rats. Hepatic glycogen decreased substantially and, as with muscle glycogen, the decrease was parallel in T and C rats. The plasma concentrations of free fatty acids were higher but lactate and alanine lower in T than in C rats. In trained rats the hormonal response to exercise is blunted partly due to higher glucose concentrations. In these rats adipose tissue sensitivity to catecholamines is increased, and changes in glucagon and insulin concentrations are not necessary for increased lipolysis and hepatic glycogen depletion during exercise.

Effects of preexercise snack feeding on endurance cycle exercise

1986 ◽  
Vol 60 (3) ◽  
pp. 980-985 ◽  
Author(s):  
J. T. Devlin ◽  
J. Calles-Escandon ◽  
E. S. Horton
Keyword(s):  
Muscle Glycogen ◽  
Endurance Performance ◽  
Snack Food ◽  
Base Line ◽  
O2 Consumption ◽  
Glycogen Depletion ◽  
Cycle Exercise ◽  
Healthy Human ◽  
Exercise Period ◽  
Male Subjects

We studied the effects of ingesting either a snack food (S) (260 kcal) or placebo (P) 30 min before intermittent cycle exercise at 70% maximal O2 consumption on endurance performance and muscle glycogen depletion in eight healthy human males. Immediately before exercise there were significantly greater increases in plasma glucose (PG) (S +28 +/- 9.7; P +0.1 +/- 0.8 mg/dl) and insulin (S +219 +/- 61.5; P -7 +/- 5.5 pmol/l) (P less than 0.05) following S feeding compared with P. These differences were no longer present by the end of the first exercise period. There were no differences in endurance times (S 52 +/- 6.4; P 48 +/- 5.6 min) or in the extent of muscle glycogen depletion following exercise (S 56 +/- 14.7; P 50 +/- 15.5 micrograms/mg protein) between the two groups. PG was maintained at base-line (prefeeding) concentrations following S, whereas there was a tendency for PG to steadily decrease after P. Total grams of carbohydrate oxidized during exercise did not differ between the two groups (S 120; P 118 g). These results demonstrate that the ingestion of a mixed-macronutrient snack 30 min before exercise does not impair endurance performance nor increase the extent of muscle glycogen depletion during high-intensity cycle exercise in untrained adult male subjects.

Body carbon dioxide storage capacity in exercise

1979 ◽  
Vol 46 (4) ◽  
pp. 811-815 ◽  
Author(s):  
N. L. Jones ◽  
J. E. Jurkowski
Keyword(s):  
Carbon Dioxide ◽  
Power Output ◽  
Storage Capacity ◽  
Co2 Storage ◽  
Progressive Increase ◽  
Co2 Output ◽  
Higher Power ◽  
Venous Pco2 ◽  
End Tidal ◽  
Mixed Venous

Body CO2 storage capacity was measured in nine subjects at two levels of exercise, approximating 30 and 60% VO2max, by measuring the excess CO2 output associated with hyperventilation at constant end-tidal PCO2, and the change in mixed venous PCO2 (PVCO2) measured by rebreathing. CO2 output was measured during 20-s periods and monitored throughout the procedure; hyperventilation was continued until CO2 output had returned to control values. Washout of CO2 was more rapid than previously found at rest, 90% of the change following an increase in ventilation occurring within 4 min. CO2 storage capacity was 1.83 +/- 0.552 (SD) ml-kg--1.Torr--1 at the lower power output and 1.19 +/- 0.490 ml-kg--1.Torr--1 at the higher power output. The CO2 storage capacity was inversely related to PVCO2. It was concluded that the body's capacity to store CO2 decreases with increasing PVCO2; this may be one factor leading to the progressive increase in pulmonary CO2 output at high levels of exercise.

Ventilation in exercise studied with circulatory occlusion

1981 ◽  
Vol 50 (4) ◽  
pp. 718-723 ◽  
Author(s):  
A. J. Sargeant ◽  
M. Y. Rouleau ◽  
J. R. Sutton ◽  
N. L. Jones
Keyword(s):  
Ventilatory Response ◽  
Initial Period ◽  
Cycle Ergometer ◽  
Similar Degree ◽  
Oxygen Intake ◽  
Venous Pco2 ◽  
End Tidal ◽  
And Control ◽  
Response To Exercise ◽  
Male Subjects

Five male subjects exercised on a cycle ergometer (100 W) for 8 min; circulation to the legs was occluded by cuffs during the first 2 and last 2 min. Ventilation (VE), oxygen intake (VO2), and carbon dioxide output (VCO2) were measured breath by breath. Repeat studies were used to follow arterial PCO2 (PaCO2) and rebreathing mixed venous PCO2 (PVCO2). The results were compared to studies without cuffing, but which were otherwise identical. The initial period of cuffing was associated with marked hyperpnea, high VE/VCO2 ratio, and low PaCO2 and PVCO2. Following release of occlusion at the end of the first 2 min, there was an immediate fall in VE, followed by an increase after an average of 12 s. VE/VCO2 fell and end-tidal PCO2 rose after 4-5 s and reached control values after 12 s. Studies during rebreathing established that CO2 reached the lungs from the legs 4-5 s after release of occlusion, and control PVCO2 was reached after 12 s. Repeated occlusion for the final 2 min of exercise was associated with hyperpnea of similar degree to the initial occlusion. An identical study performed in a patient with absent ventilatory response to CO2 and reduced ventilatory response to exercise showed normal hyperventilatory response to cuffing but did not show an increase in ventilation associated with the arrival of CO2 in the lungs, following release of occlusion. The studies confirmed the importance of CO2 in mediating rapid changes in ventilation during exercise.

Hydrogenation of nitrogen oxide on platinum-carbon catalysts in acidic medium

1981 ◽  
Vol 46 (11) ◽  
pp. 2669-2675 ◽  
Author(s):  
Ivo Paseka
Keyword(s):  
Nitrogen Oxide ◽  
Acidic Medium ◽  
Diffusion Region ◽  
Acid Solutions ◽  
Experimental Conditions ◽  
Platinum Content ◽  
Kinetically Controlled ◽  
Partial Pressures ◽  
Carbon Catalysts

Hydrogenation of nitrogen oxide in acid solutions on Pt-C catalysts proceeds in dependence on experimental conditions either in purely diffusion region or in the diffusion and kinetically controlled region. The boundary between these two processes shifts to the higher ratio of NO to H2 partial pressures with increasing platinum content and decreasing intensity of agitation.

scholarly journals Effects of Nutrient Intake Timing on Post-Exercise Glycogen Accumulation and its Related Signaling Pathways in Mouse Skeletal Muscle

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2555 ◽  
Author(s):  
Takahashi ◽  
Matsunaga ◽  
Banjo ◽  
Takahashi ◽  
Sato ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Nutrient Intake ◽  
Matched Control ◽  
Control Group ◽  
Glycogen Depletion ◽  
Post Exercise ◽  
Glycogen Accumulation ◽  
Matched Control Group ◽  
Significant Difference

We investigated the effects of nutrient intake timing on glycogen accumulation and its related signals in skeletal muscle after an exercise that did not induce large glycogen depletion. Male ICR mice ran on a treadmill at 25 m/min for 60 min under a fed condition. Mice were orally administered a solution containing 1.2 mg/g carbohydrate and 0.4 mg/g protein or water either immediately (early nutrient, EN) or 180 min (late nutrient, LN) after the exercise. Tissues were harvested at 30 min after the oral administration. No significant difference in blood glucose or plasma insulin concentrations was found between the EN and LN groups. The plantaris muscle glycogen concentration was significantly (p < 0.05) higher in the EN group—but not in the LN group—compared to the respective time-matched control group. Akt Ser473 phosphorylation was significantly higher in the EN group than in the time-matched control group (p < 0.01), while LN had no effect. Positive main effects of time were found for the phosphorylations in Akt substrate of 160 kDa (AS160) Thr642 (p < 0.05), 5'-AMP-activated protein kinase (AMPK) Thr172 (p < 0.01), and acetyl-CoA carboxylase Ser79 (p < 0.01); however, no effect of nutrient intake was found for these. We showed that delayed nutrient intake could not increase muscle glycogen after endurance exercise which did not induce large glycogen depletion. The results also suggest that post-exercise muscle glycogen accumulation after nutrient intake might be partly influenced by Akt activation. Meanwhile, increased AS160 and AMPK activation by post-exercise fasting might not lead to glycogen accumulation.

scholarly journals The Relationship between Resistance Exercise Performance and Ventilatory Efficiency after Beetroot Juice Intake in Well-Trained Athletes

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1094
Author(s):  
Noemí Serra-Payá ◽  
Manuel Vicente Garnacho-Castaño ◽  
Sergio Sánchez-Nuño ◽  
Lluís Albesa-Albiol ◽  
Montserrat Girabent-Farrés ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Exercise Test ◽  
Exercise Performance ◽  
Beetroot Juice ◽  
Experimental Conditions ◽  
Double Blind ◽  
Ventilatory Efficiency ◽  
End Tidal ◽  
Oxygen Uptake Efficiency Slope ◽  
The Relationship

The assessment of ventilatory efficiency is critical to understanding the matching of ventilation (VE) and perfusion in the lungs during exercise. This study aimed to establish a causal physiological relationship between ventilatory efficiency and resistance exercise performance after beetroot juice (BJ) intake. Eleven well-trained males performed a resistance exercise test after drinking 140 mL of BJ (~12.8 mmol NO3−) or a placebo (PL). Ventilatory efficiency was assessed by the VE•VCO2−1 slope, the oxygen uptake efficiency slope and the partial pressure of end-tidal carbon dioxide (PetCO2). The two experimental conditions were controlled using a randomized, double-blind crossover design. The resistance exercise test involved repeating the same routine twice, which consisted of wall ball shots plus a full squat (FS) with a 3 min rest or without a rest between the two exercises. A higher weight lifted was detected in the FS exercise after BJ intake compared with the PL during the first routine (p = 0.004). BJ improved the VE•VCO2−1 slope and the PetCO2 during the FS exercise in the first routine and at rest (p < 0.05). BJ intake improved the VE•VCO2−1 slope and the PetCO2 coinciding with the resistance exercise performance. The ergogenic effect of BJ could be induced under aerobic conditions at rest.

scholarly journals Endurance training reduces the contraction-induced interleukin-6 mRNA expression in human skeletal muscle

2004 ◽  
Vol 287 (6) ◽  
pp. E1189-E1194 ◽  
Author(s):  
Christian P. Fischer ◽  
Peter Plomgaard ◽  
Anne K. Hansen ◽  
Henriette Pilegaard ◽  
Bengt Saltin ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Muscle Glycogen ◽  
Human Skeletal Muscle ◽  
Acute Exercise ◽  
Glycogen Content ◽  
Knee Extensor ◽  
Exercise Induced ◽  
Response To Exercise ◽  
Resting Muscle

Contracting skeletal muscle expresses large amounts of IL-6. Because 1) IL-6 mRNA expression in contracting skeletal muscle is enhanced by low muscle glycogen content, and 2) IL-6 increases lipolysis and oxidation of fatty acids, we hypothesized that regular exercise training, associated with increased levels of resting muscle glycogen and enhanced capacity to oxidize fatty acids, would lead to a less-pronounced increase of skeletal muscle IL-6 mRNA in response to acute exercise. Thus, before and after 10 wk of knee extensor endurance training, skeletal muscle IL-6 mRNA expression was determined in young healthy men ( n = 7) in response to 3 h of dynamic knee extensor exercise, using the same relative workload. Maximal power output, time to exhaustion during submaximal exercise, resting muscle glycogen content, and citrate synthase and 3-hydroxyacyl-CoA dehydrogenase enzyme activity were all significantly enhanced by training. IL-6 mRNA expression in resting skeletal muscle did not change in response to training. However, although absolute workload during acute exercise was 44% higher ( P < 0.05) after the training period, skeletal muscle IL-6 mRNA content increased 76-fold ( P < 0.05) in response to exercise before the training period, but only 8-fold ( P < 0.05, relative to rest and pretraining) in response to exercise after training. Furthermore, the exercise-induced increase of plasma IL-6 ( P < 0.05, pre- and posttraining) was not higher after training despite higher absolute work intensity. In conclusion, the magnitude of the exercise-induced IL-6 mRNA expression in contracting human skeletal muscle was markedly reduced by 10 wk of training.

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