| Decreased PDH activation and glycogenolysis during exercise following fat adaptation with carbohydrate restoration. | |
| | |
MedLine Citation:
|
PMID: 16188909 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Five days of a high-fat diet while training, followed by 1 day of carbohydrate (CHO) restoration, increases rates of whole body fat oxidation and decreases CHO oxidation during aerobic cycling. The mechanisms responsible for these shifts in fuel oxidation are unknown but involve up- and downregulation of key regulatory enzymes in the pathways of skeletal muscle fat and CHO metabolism, respectively. This study measured muscle PDH and HSL activities before and after 20 min of cycling at 70% VO2peak and 1 min of sprinting at 150% peak power output (PPO). Estimations of muscle glycogenolysis were made during the initial minute of exercise at 70% VO2peak and during the 1-min sprint. Seven male cyclists undertook this exercise protocol on two occasions. For 5 days, subjects consumed in random order either a high-CHO (HCHO) diet (10.3 g x kg(-1) x day(-1) CHO, or approximately 70% of total energy intake) or an isoenergetic high-fat (FAT-adapt) diet (4.6 g x kg(-1) x day(-1) FAT, or 67% of total energy) while undertaking supervised aerobic endurance training. On day 6 for both treatments, subjects ingested an HCHO diet and rested before their experimental trials on day 7. This CHO restoration resulted in similar resting glycogen contents (FAT-adapt 873 +/- 121 vs. HCHO 868 +/- 120 micromol glucosyl units/g dry wt). However, the respiratory exchange ratio was lower during cycling at 70% VO2peak in the FAT-adapt trial, which resulted in an approximately 45% increase and an approximately 30% decrease in fat and CHO oxidation, respectively. PDH activity was lower at rest and throughout exercise at 70% VO2peak (1.69 +/- 0.25 vs. 2.39 +/- 0.19 mmol x kg wet wt(-1) x min(-1)) and the 1-min sprint in the FAT-adapt vs. the HCHO trial. Estimates of glycogenolysis during the 1st min of exercise at 70% VO2peak and the 1-min sprint were also lower after FAT-adapt (9.1 +/- 1.1 vs. 13.4 +/- 2.1 and 37.3 +/- 5.1 vs. 50.5 +/- 2.7 glucosyl units x kg dry wt(-1) x min(-1)). HSL activity was approximately 20% higher (P = 0.12) during exercise at 70% VO2peak after FAT-adapt. Results indicate that previously reported decreases in whole body CHO oxidation and increases in fat oxidation after the FAT-adapt protocol are a function of metabolic changes within skeletal muscle. The metabolic signals responsible for the shift in muscle substrate use during cycling at 70% VO2peak remain unclear, but lower accumulation of free ADP and AMP after the FAT-adapt trial may be responsible for the decreased glycogenolysis and PDH activation during sprinting. |
| | |
Authors:
|
Trent Stellingwerff; Lawrence L Spriet; Matthew J Watt; Nicholas E Kimber; Mark Hargreaves; John A Hawley; Louise M Burke |
Related Documents
:
|
14970749 - The distribution of white blood cell fat oxidation in health and disease. 12444309 - Does fasting during ramadan alter body composition, blood constituents and physical per... 16339329 - Effects of progressive resistance training on body composition in frail older adults: r... 14748949 - Effect of equilibrated hydration changes on total body water estimates by bioelectrical... 6394319 - Metabolic and hormonal responses to prolonged physical exercise in dogs after a single ... 22234669 - Effect of home-based exercise program on lymphedema and quality of life in female postm... 20649499 - High-intensity interval training in an adolescent with cystic fibrosis: a physiological... 11790899 - Partial body weight treadmill training in persons with chronic stroke. 7323489 - Interpretation of inert gas retention and excretion in the presence of stratified inhom... |
Publication Detail:
|
Type: Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't Date: 2005-09-27 |
Journal Detail:
|
Title: American journal of physiology. Endocrinology and metabolism Volume: 290 ISSN: 0193-1849 ISO Abbreviation: Am. J. Physiol. Endocrinol. Metab. Publication Date: 2006 Feb |
Date Detail:
|
Created Date: 2006-01-11 Completed Date: 2006-02-22 Revised Date: 2008-11-21 |
Medline Journal Info:
|
Nlm Unique ID: 100901226 Medline TA: Am J Physiol Endocrinol Metab Country: United States |
Other Details:
|
Languages: eng Pagination: E380-8 Citation Subset: IM |
Affiliation:
|
Department of Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada. trent.stellingwerff@bw.unimaas.nl |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adaptation, Physiological
/
physiology Adipose Tissue / physiology* Adult Cross-Over Studies Dietary Carbohydrates / metabolism* Exercise / physiology Glycogenolysis / physiology* Humans Muscle, Skeletal / physiology* Physical Endurance / physiology* Physical Exertion / physiology* Pyruvate Dehydrogenase Complex / metabolism* |
| Chemical | |
Reg. No./Substance:
|
0/Dietary Carbohydrates; 0/Pyruvate Dehydrogenase Complex |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Central orexin sensitivity, physical activity, and obesity in diet-induced obese and diet-resistant ...
Next Document: Hexosamines regulate sensitivity of glucose-stimulated insulin secretion in beta-cells.