The Effect of Single and Repeated Bouts of Prolonged Cycling on Leukocyte Redistribution, Neutrophil Degranulation, IL-6, and Plasma Stress Hormone Responses

2004 ◽  
Vol 14 (5) ◽  
pp. 501-516 ◽  
Author(s):  
Tzai-Li Li ◽  
Michael Gleeson
Keyword(s):  
Prolonged Exercise ◽  
Exercise Bout ◽  
Neutrophil Function ◽  
Stress Hormone ◽  
Glucose Levels ◽  
Single Bout ◽  
Lower Plasma Glucose ◽  
Neutrophil Degranulation ◽  
Hormone Responses ◽  
Experimental Trials

This study compared immunoendocrine responses to a single bout of prolonged cycling at different times of day and to a 2nd bout of cycling at the same intensity on the same day. In a counterbalanced design, 8 men participated in 3 experimental trials separated by at least 4 d. In the afternoon exercise-only trial, subjects cycled for 2 h at 60% VO2max starting at 14:00. In the other 2 trials, subjects performed either 2 bouts of cycling at 60% VO2max for 2 h (starting at 09:00 and 14:00) or a separate resting trial. The single bout of prolonged exercise performed in the afternoon induced a larger neutrophilia and monocy-tosis than the identical bout of morning exercise, possibly the result of reduced carbohydrate availability and the circadian rhythm in cortisol levels. The 2nd prolonged exercise bout caused greater immunoendocrine responses but lower plasma glucose levels and neutrophil function compared with the 1st bout.

Endurance training attenuates stress hormone responses to exercise in fasted rats

1982 ◽  
Vol 243 (1) ◽  
pp. R179-R184 ◽  
Author(s):  
W. W. Winder ◽  
M. A. Beattie ◽  
R. T. Holman
Keyword(s):  
Blood Glucose ◽  
Plasma Concentrations ◽  
Liver Glycogen ◽  
Stress Hormone ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Fasted State ◽  
Hormone Responses ◽  
Exercise Muscle ◽  
Fasted Rats

Endurance exercise training produces major adaptations in hormonal and metabolic responses to exercise. This study was designed to determine whether the differences in hormone response persist in the fasted condition when liver glycogen is depleted. Rats were run on a motor-driven rodent treadmill 5 days/wk for periods up to 2 h/day for 10 wk. Trained and nontrained rats were then fasted 24 h and were run for periods ranging from 0- to 60 min. At the end of 60 min of exercise muscle glycogen was higher in trained rats (2.9 +/- 0.3 vs. 1.1 +/- 0.1 mg/g). Blood glucose was maintained at higher levels in trained rats throughout the course of the exercise (3.2 +/- 0.1 vs. 2.3 +/- 0.1 mM after 60 min). Plasma concentrations of glucagon and epinephrine increased in both groups during the exercise but were significantly lower in trained animals. Differences between trained and nontrained animals in stress hormone responses to exercise persist in the fasted state and appear to be a consequence of the capacity of trained animals to maintain higher blood glucose levels.

Enhancement of fat metabolism by repeated bouts of moderate endurance exercise

2007 ◽  
Vol 102 (6) ◽  
pp. 2158-2164 ◽  
Author(s):  
Kazushige Goto ◽  
Naokata Ishii ◽  
Ayuko Mizuno ◽  
Kaoru Takamatsu
Keyword(s):  
Prolonged Exercise ◽  
Recovery Period ◽  
Fat Metabolism ◽  
Rest Period ◽  
Exercise Bout ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Single Trial ◽  
Repeated Trial ◽  
Single Bout

This study compared the fat metabolism between “a single bout of prolonged exercise” and “repeated bouts of exercise” of equivalent exercise intensity and total exercise duration. Seven men performed three trials: 1) a single bout of 60-min exercise (Single); 2) two bouts of 30-min exercise, separated by a 20-min rest between exercise bouts (Repeated); and 3) rest. Each exercise was performed with a cycle ergometer at 60% of maximal oxygen uptake. In the Single and Repeated trials, serum glycerol, growth hormone, plasma epinephrine, and norepinephrine concentrations increased significantly ( P < 0.05) during the first 30-min exercise bout. In the Repeated trial, serum free fatty acids (FFA), acetoacetate, and 3-hydroxybutyrate concentrations showed rapid increases ( P < 0.05) during a subsequent 20-min rest period. During the second 30-min exercise bout, FFA and epinephrine responses were significantly greater in the Repeated trial than in the Single trial ( P < 0.05). Moreover, the Repeated trial showed significantly lower values of insulin and glucose than the Single trial. During the 60-min recovery period after the exercise, FFA, glycerol, and 3-hydroxybutyrate concentrations were significantly higher in the Repeated trial than in the Single trial ( P < 0.05). The relative contribution of fat oxidation to the energy expenditure showed significantly higher values ( P < 0.05) in the Repeated trial than in the Single trial during the recovery period. These results indicate that repeated bouts of exercise cause enhanced fat metabolism compared with a single bout of prolonged exercise of equivalent total exercise duration.

Influence of Carbohydrate Supplementation on Plasma Cytokine and Neutrophil Degranulation Responses to High Intensity Intermittent Exercise

2002 ◽  
Vol 12 (2) ◽  
pp. 145-156 ◽  
Author(s):  
Nicolette C. Bishop ◽  
Michael Gleeson ◽  
Ceri W. Nicholas ◽  
Ajmol Ali
Keyword(s):  
High Intensity ◽  
Intermittent Exercise ◽  
Plasma Concentrations ◽  
Neutrophil Function ◽  
Moderate Intensity ◽  
Post Exercise ◽  
Carbohydrate Supplementation ◽  
Tnf Α ◽  
Neutrophil Degranulation ◽  
Factor Α

Ingesting carbohydrate (CHO) beverages during prolonged, continuous heavy exercise results in smaller changes in the plasma concentrations of several cytokines and attenuates a decline in neutrophil function. In contrast, ingesting CHO during prolonged intermittent exercise appears to have negligible influence on these responses, probably due to the overall moderate intensity of these intermittent exercise protocols. Therefore, we examined the effect of CHO ingestion on plasma interIeukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS)-stimuIated neutrophil degranulation responses to high-intensity intermittent running. Six trained male soccer players performed 2 exercise trials, 7 days apart, in a randomized, counterbalanced design. On each occasion, they completed six 15-min periods of intermittent running consisting of maximal sprinting interspersed with less intense periods of running and walking. Subjects consumed either CHO or artificially sweetened placebo(PLA) beverages immediately before and at 15-min intervals during the exercise. At 30 min post-exercise, CHO versus PLA was associated with a higher plasma glucose concentration (p< .01), a lower plasma cortisol and IL-6 concentration (p < .02), and fewer numbers of circulating neutrophils (p < .05). Following the exercise, LPS-stimulated elastase release per neutrophil fell 31 % below baseline values on the PLA trial (p = .06) compared with 11% on the CHO trial (p = .30). Plasma TNF-α concentration increased following the exercise (main effect of time, p < .001) but was not affected by CHO. These data indicate that CHO ingestion attenuates changes in plasma IL-6 concentration, neutrophil trafficking, and LPS-stimulated neutrophil degranulation in response to intermittent exercise that involves bouts of very high intensity exercise.

scholarly journals Lack of skeletal muscle IL-6 influences hepatic glucose metabolism in mice during prolonged exercise

2017 ◽  
Vol 312 (4) ◽  
pp. R626-R636 ◽  
Author(s):  
Lærke Bertholdt ◽  
Anders Gudiksen ◽  
Camilla L. Schwartz ◽  
Jakob G. Knudsen ◽  
Henriette Pilegaard
Keyword(s):  
Skeletal Muscle ◽  
Glucose Metabolism ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Prolonged Exercise ◽  
Hepatic Glycogen ◽  
Glucose Content ◽  
Hepatic Glucose Metabolism ◽  
Hepatic Glucose ◽  
Single Bout ◽  
Substrate Choice

The liver is essential in maintaining and regulating glucose homeostasis during prolonged exercise. IL-6 has been shown to be secreted from skeletal muscle during exercise and has been suggested to signal to the liver. Therefore, the aim of this study was to investigate the role of skeletal muscle IL-6 on hepatic glucose regulation and substrate choice during prolonged exercise. Skeletal muscle-specific IL-6 knockout (IL-6 MKO) mice (age, 12–14 wk) and littermate lox/lox (Control) mice were either rested (Rest) or completed a single bout of exercise for 10, 60, or 120 min, and the liver was quickly obtained. Hepatic IL-6 mRNA was higher at 60 min of exercise, and hepatic signal transducer and activator of transcription 3 was higher at 120 min of exercise than at rest in both genotypes. Hepatic glycogen was higher in IL-6 MKO mice than control mice at rest, but decreased similarly during exercise in the two genotypes, and hepatic glucose content was lower in IL-6 MKO than control mice at 120 min of exercise. Hepatic phosphoenolpyruvate carboxykinase mRNA and protein increased in both genotypes at 120 min of exercise, whereas hepatic glucose 6 phosphatase protein remained unchanged. Furthermore, IL-6 MKO mice had higher hepatic pyruvate dehydrogenase (PDH)Ser232 and PDHSer300 phosphorylation than control mice at rest. In conclusion, hepatic gluconeogenic capacity in mice is increased during prolonged exercise independent of muscle IL-6. Furthermore, Skeletal muscle IL-6 influences hepatic substrate regulation at rest and hepatic glucose metabolism during prolonged exercise, seemingly independent of IL-6 signaling in the liver.

Effect of a single bout of exercise and chronic exercise training on insulin sensitivity in racing sled dogs

2014 ◽  
Vol 10 (3) ◽  
pp. 167-172 ◽  
Author(s):  
S.E. Pratt-Phillips ◽  
R.J. Geor ◽  
M. Buser ◽  
A. Zirkle ◽  
A. Moore ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Exercise Training ◽  
Exercise Bout ◽  
Post Exercise ◽  
Exercise Challenge ◽  
Sled Dogs ◽  
Significant Difference ◽  
Single Bout ◽  
Three Stages

Two experiments were designed to investigate the role of exercise on insulin sensitivity (IS) in Alaskan racing sled dogs. In both experiments, IS was quantified with an isoglycemic-hyperinsulinemic clamp (IHC), whereby IS was defined as the glucose infusion rate (GIR) divided by the mean insulin concentration during the clamp. In Experiment 1, IS was quantified in 12 racing sled dogs during three stages of exercise training: unexercised for 4 months over the summer (deconditioned), and after two and four months of exercise conditioning. At each stage IS was assessed in unexercised dogs (n=6) and 60 h following a standard exercise challenge (n=6) consisting of a 35.4 km run completed in 2.5 h. In Experiment 2, IS was assessed in deconditioned dogs (n=6) and in well-conditioned dogs that had either completed a 708 km race 5-days prior (n=3) or were unraced for the previous month (n=3). In Experiment 1, there were no significant differences (Pã0.05) in GIR or IS between the three levels of conditioning, nor were there any effects of the exercise bout 60 h prior to the IHC. In Experiment 2 there was no significant difference in IS between well-conditioned dogs and untrained dogs (Pã0.05). However, dogs that completed a 708 km race 5-days prior to the IHC had a significantly higher IS than dogs that were deconditioned and those that were conditioned but unraced. These results suggest that the workload of an exercise challenge is a factor in post-exercise changes in IS but that exercise conditioning has little impact on IS in Alaskan sled dogs.

Stress, Hormone Responses, and Cancer

1986 ◽  
pp. 21-31
Author(s):  
G. M. Brown ◽  
J. Seggie ◽  
P. Ettigi
Keyword(s):  
Stress Hormone ◽  
Hormone Responses

scholarly journals Resistance training reduces the acute exercise-induced increase in muscle protein turnover

1999 ◽  
Vol 276 (1) ◽  
pp. E118-E124 ◽  
Author(s):  
S. M. Phillips ◽  
K. D. Tipton ◽  
A. A. Ferrando ◽  
R. R. Wolfe
Keyword(s):  
Resistance Training ◽  
Resistance Exercise ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Exercise Bout ◽  
Muscle Contractions ◽  
Breakdown Rates ◽  
Single Bout ◽  
Fractional Synthesis ◽  
Exercise Induced

We examined the effect of resistance training on the response of mixed muscle protein fractional synthesis (FSR) and breakdown rates (FBR) by use of primed constant infusions of [2H5]phenylalanine and [15N]phenylalanine, respectively, to an isolated bout of pleiometric resistance exercise. Trained subjects, who were performing regular resistance exercise (trained, T; n = 6), were compared with sedentary, untrained controls (untrained, UT; n = 6). The exercise test consisted of 10 sets (8 repetitions per set) of single-leg knee flexion (i.e., pleiometric muscle contraction during lowering) at 120% of the subjects’ predetermined single-leg 1 repetition maximum. Subjects exercised one leg while their contralateral leg acted as a nonexercised (resting) control. Exercise resulted in an increase, above resting, in mixed muscle FSR in both groups (UT: rest, 0.036 ± 0.002; exercise, 0.0802 ± 0.01; T: rest, 0.045 ± 0.004; exercise, 0.067 ± 0.01; all values in %/h; P< 0.01). In addition, exercise resulted in an increase in mixed muscle FBR of 37 ± 5% (rest, 0.076 ± 0.005; exercise, 0.105 ± 0.01; all values in %/h; P < 0.01) in the UT group but did not significantly affect FBR in the T group. The resulting muscle net balance (FSR − FBR) was negative throughout the protocol ( P < 0.05) but was increased in the exercised leg in both groups ( P < 0.05). We conclude that pleiometric muscle contractions induce an increase in mixed muscle protein synthetic rate within 4 h of completion of an exercise bout but that resistance training attenuates this increase. A single bout of pleiometric muscle contractions also increased the FBR of mixed muscle protein in UT but not in T subjects.

Stress, Hormone Responses, and Cancer

1978 ◽  
pp. 29-39
Author(s):  
G. M. Brown ◽  
J. Seggie ◽  
P. Ettigi
Keyword(s):  
Stress Hormone ◽  
Hormone Responses

Metabolic Fuel and Hormone Responses to Fasting in Newborn Infants

PEDIATRICS ◽  
1979 ◽  
Vol 64 (5) ◽  
pp. 613-619
Author(s):  
Charles A. Stanley ◽  
Endla K. Anday ◽  
Lester Baker ◽  
Maria Delivoria-Papadopolous
Keyword(s):  
Gestational Age ◽  
Plasma Glucose ◽  
Neonatal Period ◽  
Newborn Infants ◽  
Older Children ◽  
Glucose Levels ◽  
Metabolic Fuel ◽  
Healthy Infants ◽  
Lower Plasma Glucose ◽  
Appropriate For Gestational Age

To examine why newborn infants frequently cannot maintain adequate levels of plasma glucose in the interval between delivery and the time they are first fed, circulating metabolic fuel and regulatory hormone concentrations were determined in 44 healthy infants at the end of an eight-hour postnatal fast. Plasma glucose fell below 40 mg/100 ml prior to eight hours in four of 24 term-appropriate-for-gestational-age (AGA), two of nine preterm-AGA, five of six term-small-for-gestational-age (SGA), and three of five preterm-SGA infants. Fuel and hormone patterns in the premature and SGA infants were not different from those found in term-AGA infants. Results in these neonates differed in two areas from the response to fasting seen later in life. In fasted term-AGA infants, ketones were low (β-hydroxybutyrate 0.29 ± 0.04 mM/liter) despite elevated concentrations of fatty acid precursors (1.4 ± 0.07 mM/liter), and the group of infants studied failed to demonstrate the increase in plasma ketones with lower glucose levels (r = +.23, P = .07) which is found in older children. Levels of glucose precursors were two to three times higher in term-AGA infants (lactate 2.9 ± 0.2 mM/liter; alanine 0.48 ± 0.02 mM/liter) than levels found beyond the neonatal period and, in contrast to older children and adults, were not diminished in infants with lower plasma glucose (lactate, r = -.28, P = .035; alanine, r = -.33, P = .02). These differences between the responses to postnatal fasting and those seen beyond the neonatal period suggest that the capacity for both hepatic ketone synthesis and gluconeogenesis is not fully developed at birth.

Effects of a single bout of exercise on glucose effectiveness

1996 ◽  
Vol 80 (3) ◽  
pp. 754-759 ◽  
Author(s):  
Y. Higaki ◽  
T. Kagawa ◽  
J. Fujitani ◽  
A. Kiyonaga ◽  
M. Shindo ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Exercise Bout ◽  
Threshold Level ◽  
Tolerance Test ◽  
Cycle Ergometer ◽  
Intravenous Glucose Tolerance Test ◽  
Exhaustive Exercise ◽  
Intravenous Glucose ◽  
Glucose Effectiveness ◽  
Single Bout

The effects of a single bout of exercise on glucose effectiveness (SG) and insulin sensitivity (SI) in 22 sedentary subjects were estimated with a minimal model approach. The intravenous glucose tolerance test (IVGTT) was performed 1) 11 h after an exercise bout on a cycle ergometer at the lactate threshold level (mild exercise) for 60 min, 2) 11 h after an exercise bout at the 4 mM lactate level (hard exercise) for 36 +/- 1 min, 3) 11 h after an exhaustive-exercise bout (exhaustive exercise) for 96 +/- 7 min, or 4) without any prior exercise (control). Only the exhaustive exercise increased the glucose disappearance constant (2.69 +/- 0.28 vs. 2.05 +/- 0.13%/min; P < 0.05) and SI (15.0 +/- 2.0 vs. 10.3 +/- 0.9 x 10(-5) min/pM: P < 0.05) in comparison with the control condition. The SG and SG at zero insulin (GEZI) were not affected by any exercise condition. However, a marked individual difference in GEZI emerged after the exhaustive exercise and could be divided into two subgroups: one decreased in GEZI (0.014 +/- 0.001 vs. 0.007 +/- 0.001 min-1) and the other increased in GEZI (0.014 +/- 0.001 vs. 0.021 +/- 0.003 min-1). The former subgroup was accompanied by elevated levels of plasma creatine kinase (100 +/- 16 vs. 598 +/- 315 IU/l; P < 0.05) and myoglobin (Mb; 46 +/- 4 vs. 126 +/- 47 ng/ml; P < 0.05), whereas the latter subgroup showed no significant change in creatinine kinase (99 +/- 10 vs. 128 +/- 9 IU/l; P = 0.05) and Mb (50 +/- 7 vs. 51 +/- 4 ng/ml; P = 0.05). In both subgroups, SI was similarly increased after the exhaustive exercise. These results thus suggest that a single bout of exercise that results in muscle damage or changes in muscle permeability, as reflected in the increased creatine kinase and Mb levels, decreases GEZI, whereas exhaustive exercise without such alterations increases GEZI.

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