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.

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.

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.

Short-Term Effects of a Single Exercise Bout at Moderate Altitude on Blood Pressure

2004 ◽  
Vol 13 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Johann Auer ◽  
Robert Berent ◽  
Markus Prenninger ◽  
Thomas Weber ◽  
Klaus Kritzinger ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Outcome Measures ◽  
Exercise Bout ◽  
Exercise Duration ◽  
Moderate Altitude ◽  
Short Term ◽  
Type Design ◽  
Entire Duration ◽  
Single Bout

Context:Effects of a single bout of exercise at moderate altitude on blood pressure (BP) are largely unknown.Objective:To evaluate the effect of a single exercise bout at moderate altitude on BP.Design:Prospective, observational.Setting:Field study, Alpine mountains.Participants:127 men, 71 women (138 normotensive, 60 hypertensive).Intervention:Exercise duration: 2.5 ± 0.4 h; 650-m difference in altitude.Main Outcome Measures:BP and heart rate (HR).Results:Hypertensives had (1) higher systolic BP (SBP) and diastolic BP (DBP) before exercise (P< .01), whereas this difference was lost during exercise; (2) increased HR during the entire duration of exercise; and (3) significantly decreased SBP and DBP (P< .05) throughout the entire period of exercise.Conclusions:Exposure to a single exercise bout at moderate altitude is associated with a transient decrease in SBP and DBP, which is more pronounced in hypertensives.

Effect of initial muscle glycogen levels on protein catabolism during exercise

1980 ◽  
Vol 48 (4) ◽  
pp. 624-629 ◽  
Author(s):  
P. W. Lemon ◽  
J. P. Mullin
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Protein Breakdown ◽  
Protein Catabolism ◽  
Serum Urea ◽  
Serial Samples ◽  
Serum And Urine

Serum urea increases with exercise duration suggest prolonged exercise may be analogous to starvation where protein catabolism is known to occur. The purpose of this investigation was to alter muscle glycogen levels and to study the effect on protein catabolism. Six subjects (27-30 yr) pedaled a cycle ergometer for 1 h at 61% VO2max (mean VO2 = 2.33 +/- 0.7 1 . min-1) 1) after CHO loading (CHOL) and 2) after CHO depletion (CHOD). The following urea N measures were made: pre-exercise serum and urine, exercise serum and sweat (15-min serial samples), and serum and urine during 240 recovery min. Results demonstrated that 1) exercise serum urea N increased in CHOD attaining significance (P less than 0.01) at 60 min; 2) serum urea N increases continued into recovery at all measurement points of CHOD (P less than 0.01) and at 240 min of CHOL (P less than 0.05); 3) sweat urea N increased 154.2-fold (CHOD) and 65.6-fold (CHOL) (P less than 0.05). Calculations indicate that CHOD sweat urea N excretion was equivalent to a protein breakdown of 13.7 g . h-1 or 10.4% of the total caloric cost. It was concluded that protein is utilized during exercise to a greater extent than is generally assumed and that under certain conditions protein carbon may contribute significantly to exercise caloric cost.

Core temperature "null zone"

1991 ◽  
Vol 71 (4) ◽  
pp. 1289-1295 ◽  
Author(s):  
I. B. Mekjavic ◽  
C. J. Sundberg ◽  
D. Linnarsson
Keyword(s):  
Core Temperature ◽  
Recovery Period ◽  
Rest Period ◽  
Cycle Ergometer ◽  
Work Rate ◽  
The Core ◽  
Maximum Work ◽  
Male Subjects ◽  
Shivering Thermogenesis ◽  
Peak Value

An experimental protocol was designed to investigate whether human core temperature is regulated at a “set point” or whether there is a neutral zone between the core thresholds for shivering thermogenesis and sweating. Nine male subjects exercised on an underwater cycle ergometer at a work rate equivalent to 50% of their maximum work rate. Throughout an initial 2-min rest period, the 20-min exercise protocol, and the 100-min recovery period, subjects remained immersed to the chin in water maintained at 28 degrees C. On completion of the exercise, the rate of forehead sweating (Esw) decayed from a mean peak value of 7.7 +/- 4.2 (SD) to 0.6 +/- 0.3 g.m-2.min-1, which corresponds to the rate of passive transpiration, at core temperatures of 37.42 +/- 0.29 and 37.39 +/- 0.48 degrees C, as measured in the esophagus (Tes) and rectum (Tre), respectively. Oxygen uptake (VO2) decreased rapidly from an exercising level of 2.11 +/- 0.25 to 0.46 +/- 0.09 l/min within 4 min of the recovery period. Thereafter, VO2 remained stable for approximately 20 min, eventually increased with progressive cooling of the core region, and was elevated above the median resting values determined between 15 and 20 min at Tes = 36.84 +/- 0.38 degrees C and Tre = 36.80 +/- 0.39 degrees C. These results indicate that the core temperatures at which sweating ceases and shivering commences are significantly different (P less than 0.001) regardless of whether core temperature is measured within the esophagus or rectum.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Sprint training reduces urinary purine loss following intense exercise in humans

2006 ◽  
Vol 31 (6) ◽  
pp. 702-708 ◽  
Author(s):  
Christos G. Stathis ◽  
Michael F. Carey ◽  
Alan Hayes ◽  
Andrew P. Garnham ◽  
Rodney J. Snow
Keyword(s):  
Uric Acid ◽  
Performance Test ◽  
Recovery Period ◽  
Rest Period ◽  
Cycle Ergometer ◽  
Sprint Training ◽  
Intense Exercise ◽  
Before And After ◽  
Exercise Induced ◽  
Male Subjects

The influence of sprint training on endogenous urinary purine loss was examined in 7 active male subjects (age, 23.1 ± 1.8 y; body mass, 76.1 ± 3.1 kg; VO2 peak, 56.3 ± 4.0 mL·kg–1·min–1). Each subject performed a 30 s sprint performance test (PT), before and after 7 d of sprint training. Training consisted of 15 sprints, each lasting 10 s, on an air-braked cycle ergometer performed twice each day. A rest period of 50 s separated each sprint during training. Sprint training resulted in a 20% higher muscle ATP immediately after PT, a lower IMP (57% and 89%, immediately after and 10 min after PT, respectively), and inosine accumulation (53% and 56%, immediately after and 10 min after the PT, respectively). Sprint training also attenuated the exercise-induced increases in plasma inosine, hypoxanthine (Hx), and uric acid during the first 120 min of recovery and reduced the total urinary excretion of purines (inosine + Hx + uric acid) in the 24 h recovery period following intense exercise. These results show that intermittent sprint training reduces the total urinary purine excretion after a 30 s sprint bout.

Lymphocyte proliferation responses after exercise in men: fitness, intensity, and duration effects

1991 ◽  
Vol 70 (1) ◽  
pp. 179-185 ◽  
Author(s):  
B. MacNeil ◽  
L. Hoffman-Goetz ◽  
A. Kendall ◽  
M. Houston ◽  
Y. Arumugam
Keyword(s):  
T Cell ◽  
Concanavalin A ◽  
Lymphocyte Proliferation ◽  
Exercise Bout ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Control Group ◽  
Lymphocyte Function ◽  
Fitness Level ◽  
Mixed Control

This study investigated the effects of intensity and duration of exercise on lymphocyte proliferation as a measure of immunologic function in men of defined fitness. Three fitness groups--low [maximal O2 uptake (VO2max) = 44.9 +/- 1.5 ml O2.kg-1.min-1 and sedentary], moderate (VO2max = 55.2 +/- 1.6 ml O2.kg-1.min-1 and recreationally active), and high (VO2max = 63.3 +/- 1.8 ml O2.kg-1.min-1 and endurance trained)--and a mixed control group (VO2max = 52.4 +/- 2.3 ml O2.kg-1.min-1) participated in the study. Subjects completed four randomly ordered cycle ergometer rides: ride 1, 30 min at 65% VO2max; ride 2, 60 min at 30% VO2max; ride 3, 60 min at 75% VO2max; and ride 4, 120 min at 65% VO2max. Blood samples were obtained at various times before and after the exercise sessions. Lymphocyte responses to the T cell mitogen concanavalin A were determined at each sample time through the incorporation of radiolabeled thymidine [( 3H]TdR). Despite differences in resting levels of [3H]TdR uptake, a consistent depression in mitogenesis was present 2 h after an exercise bout in all fitness groups. The magnitude of the reduction in T cell mitogenesis was not affected by an increase in exercise duration. A trend toward greater reduction was present in the highly fit group when exercise intensity was increased. The reduction in lymphocyte proliferation to the concanavalin A mitogen after exercise was a short-term phenomenon with recovery to resting (preexercise) values 24 h after cessation of the work bout. These data suggest that single sessions of submaximal exercise transiently reduce lymphocyte function in men and that this effect occurs irrespective of subject fitness level.

Effects of Split Exercise Sessions on Excess Postexercise Oxygen Consumption and Resting Metabolic Rate

1998 ◽  
Vol 23 (5) ◽  
pp. 433-443 ◽  
Author(s):  
Khalid S. Almuzaini ◽  
Jeffrey A. Potteiger ◽  
Samuel B. Green
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Key Words ◽  
Resting Metabolic Rate ◽  
Exercise Bout ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Exercise Session ◽  
Male Volunteers ◽  
Excess Postexercise Oxygen Consumption

This study involved examining how splitting a 30-min exercise bout on a cycle ergometer into two equal sessions affects excess postexercise oxygen consumption (EPOC) and resting metabolic rate (RMR). In this study, 10 male volunteers (age = 23 ± 3.8) participated in two exercise trials, which were randomly assigned in a counterbalanced design and separated by 40 hr. One trial was 30 min of exercise at 70% [Formula: see text](CONT), followed by a 40-min measurement of EPOC. The second trial was divided into two 15-min sessions (SPLIT), separated by 6 hr. A 20 min measurement of EPOC followed each SPLIT session. Results indicated that the combined magnitude of EPOCs from SPLIT (7,410 ± 1,851 ml) was significantly greater than that from CONT (5,278 ± 1,305 ml). Data indicate that dividing a 30-min exercise session into two parts for these individuals significantly increases magnitude of EPOC but does not affect RMR. Key words: EPOC, RMR,[Formula: see text], exercise duration

Hyperammoniemia during prolonged exercise: an effect of glycogen depletion?

1988 ◽  
Vol 65 (6) ◽  
pp. 2475-2477 ◽  
Author(s):  
S. Broberg ◽  
K. Sahlin
Keyword(s):  
Blood Lactate ◽  
Prolonged Exercise ◽  
Venous Blood ◽  
Work Load ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Glycogen Depletion ◽  
Recovery Exercise ◽  
Low Levels

Eight healthy men exercised to exhaustion on a cycle ergometer at a work load of 176 +/- 9 (SE) W corresponding to 67% (range 63-69%) of their maximal O2 uptake (exercise I). Exercise of the same work load was repeated after 75 min of recovery (exercise II). Exercise duration (range) was 65 (50-90) and 21 (14-30) min for exercise I and II, respectively. Femoral venous blood samples were obtained before and during exercise and analyzed for NH3 and lactate. Plasma NH3 was 12 +/- 2 and 19 +/- 6 mumol/l before exercise I and II, respectively and increased during exercise to exhaustion to peak values of 195 +/- 29 (exercise I) and 250 +/- 30 (exercise II) mumol/l, respectively. Plasma NH3 increased faster during exercise II compared with exercise I and at the end of exercise II was threefold higher than the value for the corresponding time of exercise I (P less than 0.001). Blood lactate increased during exercise I and after 20 min of exercise was 3.7 +/- 0.4 mmol/l and remained unchanged until exhaustion. During exercise II blood lactate increased less than during exercise I. It is concluded that long-term exercise to exhaustion results in large increases in plasma NH3 despite relatively low levels of blood lactate. It is suggested that the faster increase in plasma NH3 during exercise II (vs. exercise I) reflects an increased formation in the working muscle that may be caused by low glycogen levels and impairment of the ATP resynthesis.

Excess postexercise oxygen consumption and recovery rate in trained and untrained subjects

1997 ◽  
Vol 83 (1) ◽  
pp. 153-159 ◽  
Author(s):  
Kevin R. Short ◽  
Darlene A. Sedlock
Keyword(s):  
Oxygen Consumption ◽  
Recovery Rate ◽  
Recovery Period ◽  
Rest Period ◽  
Recovery Phase ◽  
Cycle Ergometer ◽  
Peak Oxygen Consumption ◽  
Fitness Level ◽  
Relative Decline ◽  
Excess Postexercise Oxygen Consumption

Short, Kevin R., and Darlene A. Sedlock. Excess postexercise oxygen consumption and recovery rate in trained and untrained subjects. J. Appl. Physiol.83(1): 153–159, 1997.—The purpose of this study was to determine whether aerobic fitness level would influence measurements of excess postexercise oxygen consumption (EPOC) and initial rate of recovery. Twelve trained [Tr; peak oxygen consumption (V˙o 2 peak) = 53.3 ± 6.4 ml ⋅ kg−1 ⋅ min−1] and ten untrained (UT;V˙o 2 peak = 37.4 ± 3.2 ml ⋅ kg−1 ⋅ min−1) subjects completed two 30-min cycle ergometer tests on separate days in the morning, after a 12-h fast and an abstinence from vigorous activity of 24 h. Baseline metabolic rate was established during the last 10 min of a 30-min seated preexercise rest period. Exercise workloads were manipulated so that they elicited the same relative, 70%V˙o 2 peak (W70%), or the same absolute, 1.5 l/min oxygen uptake (V˙o 2) (W1.5), intensity for all subjects, respectively. RecoveryV˙o 2, heart rate (HR), and respiratory exchange ratio (RER) were monitored in a seated position until baseline V˙o 2 was reestablished. Under both exercise conditions, Tr had shorter EPOC duration (W70% = 40 ± 15 min, W1.5 = 21 ± 9 min) than UT (W70% = 50 ± 14 min; W1.5 = 39 ± 14 min), but EPOC magnitude (Tr: W70% = 3.2 ± 1.0 liters O2, W1.5 = 1.5 ± 0.6 liters O2; UT: W70% = 3.5 ± 0.9 liters O2, W1.5 = 2.4 ± 0.6 liters O2) was not different between groups. The similarity of Tr and UT EPOC accumulation in the W70% trial is attributed to the parallel decline in absolute V˙o 2 during most of the initial recovery period. Tr subjects had faster relative decline during the fast-recovery phase, however, when a correction for their higher exerciseV˙o 2 was taken. Postexercise V˙o 2 was lower for Tr group for nearly all of the W1.5 trial and particularly during the fast phase. Recovery HR kinetics were remarkably similar for both groups in W70%, but recovery was faster for Tr during W1.5. RER values were at or below baseline throughout much of the recovery period in both groups, with UT experiencing larger changes than Tr in both trials. These findings indicate that Tr individuals have faster regulation of postexercise metabolism when exercising at either the same relative or same absolute work rate.

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