Substrate metabolism when subjects are fed carbohydrate during exercise

1999 ◽  
Vol 276 (5) ◽  
pp. E828-E835 ◽  
Author(s):  
Jeffrey F. Horowitz ◽  
Ricardo Mora-Rodriguez ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
Plasma Insulin ◽  
Fat Oxidation ◽  
Insulin Concentration ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
Low Intensity ◽  
Low Intensity Exercise

This study determined the effect of carbohydrate ingestion during exercise on the lipolytic rate, glucose disappearance from plasma (Rd Glc), and fat oxidation. Six moderately trained men cycled for 2 h on four separate occasions. During two trials, they were fed a high-glycemic carbohydrate meal during exercise at 30 min (0.8 g/kg), 60 min (0.4 g/kg), and 90 min (0.4 g/kg); once during low-intensity exercise [25% peak oxygen consumption (V˙o 2 peak)] and once during moderate-intensity exercise (68%V˙o 2 peak). During two additional trials, the subjects remained fasted (12–14 h) throughout exercise at each intensity. After 55 min of low-intensity exercise in fed subjects, hyperglycemia (30% increase) and a threefold elevation in plasma insulin concentration ( P < 0.05) were associated with a 22% suppression of lipolysis compared with when subjects were fasted (5.2 ± 0.5 vs. 6.7 ± 1.2 μmol ⋅ kg−1 ⋅ min−1, P < 0.05), but fat oxidation was not different from fasted levels at this time. Fat oxidation when subjects were fed carbohydrate was not reduced below fasting levels until 80–90 min of exercise, and lipolysis was in excess of fat oxidation at this time. The reduction in fat oxidation corresponded in time with the increase in Rd Glc. During moderate-intensity exercise, the very small elevation in plasma insulin concentration (∼3 μU/ml; P < 0.05) during the second hour of exercise when subjects were fed vs. when they were fasted slightly attenuated lipolysis ( P < 0.05) but did not increase Rd Glc or suppress fat oxidation. These findings indicate that despite a suppression of lipolysis after carbohydrate ingestion during exercise, the lipolytic rate remained in excess and thus did not limit fat oxidation. Under these conditions, a reduction in fat oxidation was associated in time with an increase in glucose uptake.

Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise

1997 ◽  
Vol 273 (4) ◽  
pp. E768-E775 ◽  
Author(s):  
Jeffrey F. Horowitz ◽  
Ricardo Mora-Rodriguez ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
Oxygen Consumption ◽  
Plasma Insulin ◽  
Fat Oxidation ◽  
Insulin Concentration ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
The Mean

This study determined if the suppression of lipolysis after preexercise carbohydrate ingestion reduces fat oxidation during exercise. Six healthy, active men cycled 60 min at 44 ± 2% peak oxygen consumption, exactly 1 h after ingesting 0.8 g/kg of glucose (Glc) or fructose (Fru) or after an overnight fast (Fast). The mean plasma insulin concentration during the 50 min before exercise was different among Fast, Fru, and Glc (8 ± 1, 17 ± 1, and 38 ± 5 μU/ml, respectively; P< 0.05). After 25 min of exercise, whole body lipolysis was 6.9 ± 0.2, 4.3 ± 0.3, and 3.2 ± 0.5 μmol ⋅ kg−1 ⋅ min−1and fat oxidation was 6.1 ± 0.2, 4.2 ± 0.5, and 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1during Fast, Fru, and Glc, respectively (all P < 0.05). During Fast, fat oxidation was less than lipolysis ( P < 0.05), whereas fat oxidation approximately equaled lipolysis during Fru and Glc. In an additional trial, the same subjects ingested glucose (0.8 g/kg) 1 h before exercise and lipolysis was simultaneously increased by infusing Intralipid and heparin throughout the resting and exercise periods (Glc+Lipid). This elevation of lipolysis during Glc+Lipid increased fat oxidation 30% above Glc (4.0 ± 0.4 vs. 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1; P < 0.05), confirming that lipolysis limited fat oxidation. In summary, small elevations in plasma insulin before exercise suppressed lipolysis during exercise to the point at which it equaled and appeared to limit fat oxidation.

Training-induced alterations in fat and carbohydrate metabolism during exercise in elderly subjects

1998 ◽  
Vol 274 (5) ◽  
pp. E785-E790 ◽  
Author(s):  
Shahid Sial ◽  
Andrew R. Coggan ◽  
Robert C. Hickner ◽  
Samuel Klein
Keyword(s):  
Fatty Acid ◽  
Endurance Training ◽  
Average Rate ◽  
Fat Oxidation ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Elderly Subjects ◽  
Elderly Persons ◽  
Moderate Intensity Exercise ◽  
Significant Change

Compared with young adults, fat oxidation is lower in elderly persons during endurance exercise performed at either the same absolute or relative intensity. We evaluated the effect of 16 wk of endurance training on fat and glucose metabolism during 60 min of moderate intensity exercise [50% of pretraining peak oxygen consumption (V˙o2 peak)] in six elderly men and women (74 ± 2 yr). Training caused a 21% increase in meanV˙o2 peak. The average rate of fat oxidation during exercise was greater after (221 ± 28 μmol/min) than before (166 ± 17 μmol/min) training ( P = 0.002), and the average rate of carbohydrate oxidation during exercise was lower after (3,180 ± 461 μmol/min) than before (3,937 ± 483 μmol/min) training ( P = 0.003). Training did not cause a significant change in glycerol rate of appearance (Ra), free fatty acid (FFA) Ra, and FFA rate of disappearance during exercise. However, glucose Raduring exercise was lower after (1,027 ± 95 μmol/min) than before (1,157 ± 69 μmol/min) training ( P = 0.01). These results demonstrate that a 16-wk period of endurance training increases fat oxidation without a significant change in lipolysis (glycerol Ra) or FFA availability (FFA Ra) during exercise in elderly subjects. Therefore, the training-induced increase in fat oxidation during exercise is likely related to alterations in skeletal muscle fatty acid metabolism.

scholarly journals The Effect of Low and Moderate Exercise on Hyperuricemia: Protocol for a Randomized Controlled Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuning Hou ◽  
Renyan Ma ◽  
Song Gao ◽  
Keneilwe Kenny Kaudimba ◽  
Hongmei Yan ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Heart Rate ◽  
Exercise Group ◽  
Moderate Intensity ◽  
Controlled Study ◽  
Control Group ◽  
Maximum Heart Rate ◽  
Moderate Intensity Exercise ◽  
Low Intensity ◽  
Low Intensity Exercise

BackgroundHyperuricemia (HUA) is a metabolic disease by purine metabolism disorders. It is a risk factor for many chronic diseases, including diabetes, hypertension, and heart disease. Studies have shown that exercise can effectively reduce serum uric acid (SUA), but the optimal exercise dose, intensity, and mode of exercise for improving HUA have not been verified in clinical studies. Therefore, this study aims to explore the effect of different exercise intensities in improving SUA of patients with HUA.Methods and AnalysisA randomized, single-blind, parallel controlled trial will be conducted in this study. 186 HUA patients who meet the inclusion criteria will be randomly divided into a 1:1:1 ratio (1): control group (2), low-intensity exercise group (brisk walking, 57-63% maximum heart rate, 150 min/week, 12 months), and (3) moderate-intensity exercise group (jogging, 64-76% maximum heart rate, 150 min/week, 12 months). The three groups of subjects will receive the same health education and prohibition of high-purine diet during the intervention period. The primary outcomes will be SUA concentration, SUA concentration change (mg/dL), SUA change rate (%), and the proportion of HUA patients. Secondary outcomes will include anthropometric parameters (body weight, waist circumference, hip circumference, BMI); physiological indicators (blood pressure, grip, vital capacity, maximum oxygen); biochemical indicators (blood lipid, blood sugar, liver enzyme, creatinine, and blood urea nitrogen). Each group of patients will go through an assessment at baseline, 3rd, 6th, and 12th months.DiscussionThis study will evaluate the effect of 12-month low-intensity exercise and moderate-intensity exercise on HUA patients. We hypothesize that both low-intensity and moderate-intensity exercise would improve HUA as compared with no-exercise control, and that moderate-intensity exercise would be more effective than low-intensity exercise in improving HUA. These results can provide a basis for the current physical activity guidelines for HUA’s healthy lifestyle management.Ethics and DisseminationThis study has been approved by the Ethical Review Committee of the Shanghai University of Sport (approval number: 102772020RT005). Informed consent will be obtained from all participants or their guardians. The authors intend to submit the study findings to peer-reviewed journals or academic conferences to be published.Clinical Trial RegistrationChinese Clinical Trial Registry, identifier ChiCTR2100042643.

scholarly journals Impact of Low Intensity Exercise on Liver Enzymes (ALT & ALP)

2021 ◽  
pp. 370-377
Author(s):  
Alamgir Khan ◽  
Muhammad Zafar Iqbal Butt ◽  
Shahzaman Khan ◽  
Sobia Nazir ◽  
Ejaz Asghar ◽  
...  
Keyword(s):  
Liver Enzymes ◽  
Daily Basis ◽  
Moderate Intensity ◽  
Control Group ◽  
Moderate Intensity Exercise ◽  
Low Intensity ◽  
Post Test ◽  
Low Intensity Exercise ◽  
The Impact ◽  
Experimental Group

This particular research study was basically carried out for the purpose to examine the impact of low intensity exercise on two particular liver enzymes i.e. alanine transaminase (ALT) and alkaline phosphate (ALP). 20 Non sportsmen were selected as subjects of the study (n=20, age 20 to 30 years (20.95±3.79), Body Mass Index (BMI) from 18 to 30 (25.90±5.54). Similarly the subjects were divided into two groups (Experimental Group and Control Group) through the application of International Physical Activity Questionnaire (IPAQ) and measurement of Maximum Heart Rate (MHR). 12 weeks self-made low intensity exercise protocol was applied to an experimental group.  5ml blood was collected from all subjects to measure the effect of low intensity exercise on ALT and ALP. The data of pre and post-test were processed through SPSS version 24. Based on analysis and findings, the researcher concluded that in experimental group (EXG) the level of ALT and ALP was found significantly higher (p<0.05) as compared to control group (CG). Based on conclusion, it is hereby recommended by the researcher that for the purpose to promote the functional capacity of liver, low as well as moderate intensity exercise should be performed on daily basis. In addition, in this study due to lack of financial resources, two basic liver enzymes i.e.ALT and ALP were measured, therefore the other enzymes like as AST and bilirubin also need to be examined in such other research studies.

Effect of Carbohydrate Ingestion Subsequent to Carbohydrate Supercompensation on Endurance Performance

1995 ◽  
Vol 5 (4) ◽  
pp. 329-343 ◽  
Author(s):  
Jie Kang ◽  
Robert J. Robertson ◽  
Bart G. Denys ◽  
Sergio G. DaSilva ◽  
Paul Visich ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Endurance Performance ◽  
Carbohydrate Oxidation ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Time To Exhaustion ◽  
Glycerol Concentration ◽  
Moderate Intensity Exercise ◽  
Carbohydrate Ingestion ◽  
Glucose Levels

This investigation determined whether carbohydrate ingestion during prolonged moderate-intensity exercise enhanced endurance performance when the exercise was preceded by carbohydrate supercompensation. Seven male trained cyclists performed two trials at an initial power output corresponding to 71 ± 1 % of their peak oxygen consumption. During the trials, subjects ingested either a 6% glucose/sucrose (C) solution or an equal volume of artificially flavored and sweetened placebo (P) every 20 min throughout exercise. Both C and P were preceded by a 6-day carbohydrate supercompensation procedure in which subjects undertook a depletion-taper exercise sequence in conjunction with a moderate- and high-carbohydrate diet regimen. Statistical analysis of time to exhaustion, plasma glucose concentration, carbohydrate oxidation rate, fat oxidation rate, and plasma glycerol concentration indicated that in spite of a carbohydrate supercompensation procedure administered prior to exercise, carbohydrate ingestion during exercise can exert an additional ergogenic effect by preventing a decline in blood glucose levels and maintaining carbohydrate oxidation during the later stages of moderate-intensity exercise.

Comparison of thermogenic effect of fructose and glucose in normal humans

1986 ◽  
Vol 250 (6) ◽  
pp. E718-E724 ◽  
Author(s):  
L. Tappy ◽  
J. P. Randin ◽  
J. P. Felber ◽  
R. Chiolero ◽  
D. C. Simonson ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Lipid Oxidation ◽  
Plasma Insulin ◽  
Carbohydrate Oxidation ◽  
Insulin Concentration ◽  
Adrenergic Blockade ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
Glucose Ingestion ◽  
Adrenergic Nervous System

After nutrient ingestion there is an increase in energy expenditure that has been referred to as dietary-induced thermogenesis. In the present study we have employed indirect calorimetry to compare the increment in energy expenditure after the ingestion of 75 g of glucose or fructose in 17 healthy volunteers. During the 4 h after glucose ingestion the plasma insulin concentration increased by 33 +/- 4 microU/ml and this was associated with a significant increase in carbohydrate oxidation and decrement in lipid oxidation. Energy expenditure increased by 0.08 +/- 0.01 kcal/min. When fructose was ingested, the plasma insulin concentration increased by only 8 +/- 2 microU/ml vs. glucose. Nonetheless, the increments in carbohydrate oxidation and decrement in lipid oxidation were significantly greater than with glucose. The increment in energy expenditure was also greater with fructose. When the mean increment in plasma insulin concentration after fructose was reproduced using the insulin clamp technique, the increase in carbohydrate oxidation and decrement in lipid oxidation were markedly reduced compared with the fructose-ingestion study; energy expenditure failed to increase above basal levels. To examine the role of the adrenergic nervous system in fructose-induced thermogenesis, fructose ingestion was also performed during beta-adrenergic blockade with propranolol. The increase in energy expenditure during fructose plus propranolol was lower than with fructose ingestion alone. These results indicate that the stimulation of thermogenesis after carbohydrate ingestion is related to an augmentation of cellular metabolism and is not dependent on an increase in the plasma insulin concentration per se.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Increasing skeletal muscle carnitine content in older individuals increases whole‐body fat oxidation during moderate‐intensity exercise

Aging Cell ◽  
2021 ◽  
Vol 20 (2) ◽  
Author(s):  
Carolyn Chee ◽  
Chris E. Shannon ◽  
Aisling Burns ◽  
Anna L. Selby ◽  
Daniel Wilkinson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Moderate Intensity ◽  
Older Individuals ◽  
Moderate Intensity Exercise

scholarly journals 146 Nutritional Advances in Fetal and neonatal development: effect of fatty acid supplementation

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 121-122
Author(s):  
Alejandro E Relling
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Plasma Insulin ◽  
Linear Increase ◽  
Late Gestation ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Pufa Supplementation ◽  
Epa And Dha ◽  
Offspring Growth

Abstract Data from a series of experiments demonstrates that maternal supply of polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), during late gestation affects offspring growth. The increase in growth is independent on the fatty acid supplemented during the growing or finishing phase of the offspring; but it is sex dependent. Dam PUFA supplementation increases wether growth. Supplementation with EPA and DHA to pregnant ewes and to their offspring after weaning showed a treatment interaction in mRNA concentration of hypothalamic neuropeptides associated with dry matter intake (DMI) regulation. A dose increased in EPA and DHA in pregnant ewe diets shows a linear increase in growth, but a quadratic change in DMI or feed efficiency; growth was associated with a linear increase in plasma glucose concentration and a linear decrease in plasma ghrelin concentration. In lambs born from ewes supplemented with different sources of FA during a glucose tolerance test; males’ plasma insulin concentration increased as FA unsaturation degree increased in the dam diet, the opposite happened with females’ plasma insulin concentration. Recent data from our lab showed that the supplementation with EPA and DHA during the last third of gestation to pregnant ewes increased liver and small intestine global DNA methylation and small intestine transporters for amino acids in the fetus. Despite EPA and DHA during late gestation increase growth in the offspring; when EPA and DHA were supplemented in early gestation, offspring growth was lesser that lambs born from ewes supplemented a saturated and monounsaturated lipid. The reason for the difference in results it is not clear. However, more studies focusing in some aspect of the biology will help to understand what specific fatty acid needs to be supplemented at different stages of gestation to improve offspring growth.

scholarly journals Fetal growth, glucose tolerance and plasma insulin concentration in rats given a marginal-zinc diet in the latter stages of pregnancy

1988 ◽  
Vol 59 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Susan Southon ◽  
Susan J. Fairweather-Tait ◽  
Christine M. Williams
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Oral Glucose ◽  
Fetal Blood ◽  
Plasma Insulin Concentration ◽  
Pregnant Rats ◽  
Zn Content ◽  
Tail Blood

1. Wistar rats were fed on a control semi-synthetic diet throughout pregnancy, or a control diet in the first 2 weeks and a marginal-zinc diet in the 3rd week of pregnancy. On day 20, after an overnight fast, half the animals in each group were given glucose by gavage and the 0–30 min rise in blood glucose measured in tail blood. After 60 min blood was taken by cardiac puncture for glucose and insulin assay. Maternal pancreases were removed and the Zn contents measured. Fetuses from each litter were combined for wet/dry weights, protein and DNA determinations.2. Plasma insulin concentration was higher, and glucose concentration and pancreatic Zn content lower, in pregnantv. non-pregnant animals of similar age, fed on the same diet. Pancreatic Zn content was lowest in the marginal-Zn group of pregnant rats. Fetuses from mothers fed on the marginal-Zn diet during the last week of pregnancy were slightly heavier than controls and had a significantly higher protein: DNA ratio. The 0–30 min rise in blood glucose was significantly greater in the marginal-Zn animals.3. In a second experiment, pregnant rats were given similar diets to those used in the first study, but the marginal-Zn diet was given for a shorter period (days 15–19 of pregnancy). On day 19 the rats were meal-fed and on day 20, after an overnight fast, an oral glucose dose was administered. Tail-blood was taken at timed intervals up to 60 min post-dosing for glucose assay. Both maternal and fetal blood glucose and insulin concentration was measured 70 min post-dosing.4. Values for maternal and fetal blood glucose and plasma insulin, measured 70 min after the administration of a glucose dose, were similar in the two groups, but the initial rise in blood glucose concentration was again significantly higher in pregnant rats given the marginal-Zn diet towards term.5. It is suggested that the change in growth and composition, observed in fetuses from rats given a marginal-Zn diet in later pregnancy, is associated with altered maternal carbohydrate metabolism.

scholarly journals The effect of acetoacetate on plasma insulin concentration

1971 ◽  
Vol 125 (2) ◽  
pp. 541-544 ◽  
Author(s):  
R. A. Hawkins ◽  
K. G. M. M. Alberti ◽  
C. R. S. Houghton ◽  
D. H. Williamson ◽  
H. A. Krebs
Keyword(s):  
Fatty Acids ◽  
Blood Glucose ◽  
Free Fatty Acids ◽  
Glucose Concentration ◽  
Plasma Insulin ◽  
Blood Glucose Concentration ◽  
Diabetic Rats ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Arterial Blood

1. Sodium acetoacetate was infused into the inferior vena cava of fed rats, 48h-starved rats, and fed streptozotocin-diabetic rats treated with insulin. Arterial blood was obtained from a femoral artery catheter. 2. Acetoacetate infusion caused a fall in blood glucose concentration in fed rats from 6.16 to 5.11mm in 1h, whereas no change occurred in starved or fed–diabetic rats. 3. Plasma free fatty acids decreased within 10min, from 0.82 to 0.64mequiv./l in fed rats, 1.16 to 0.79mequiv./l in starved rats and 0.83 to 0.65mequiv./l in fed–diabetic rats. 4. At 10min the plasma concentration rose from 20 to 49.9μunits/ml in fed unanaesthetized rats and from 6.4 to 18.5μunits/ml in starved rats. There was no change in insulin concentration in the diabetic rats. 5. Nembutal-anaesthetized fed rats had a more marked increase in plasma insulin concentration, from 30 to 101μunits/ml within 10min. 6. A fall in blood glucose concentration in fed rats and a decrease in free fatty acids in both fed and starved rats is to be expected as a consequence of the increase in plasma insulin. 7. The fall in the concentration of free fatty acids in diabetic rats may be due to a direct effect of ketone bodies on adipose tissue. A similar effect on free fatty acids could also be operative in normal fed or starved rats.

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