| Beneficial metabolic adaptations due to endurance exercise training in the fasted state. | |
| | |
MedLine Citation:
|
PMID: 21051570 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Training with limited carbohydrate availability can stimulate adaptations in muscle cells to facilitate energy production via fat oxidation. Here we investigated the effect of consistent training in the fasted state, vs. training in the fed state, on muscle metabolism and substrate selection during fasted exercise. Twenty young male volunteers participated in a 6-wk endurance training program (1-1.5 h cycling at ∼70% Vo(₂max), 4 days/wk) while receiving isocaloric carbohydrate-rich diets. Half of the subjects trained in the fasted state (F; n = 10), while the others ingested ample carbohydrates before (∼160 g) and during (1 g·kg body wt⁻¹·h⁻¹) the training sessions (CHO; n = 10). The training similarly increased Vo(₂max) (+9%) and performance in a 60-min simulated time trial (+8%) in both groups (P < 0.01). Metabolic measurements were made during a 2-h constant-load exercise bout in the fasted state at ∼65% pretraining Vo(₂max). In F, exercise-induced intramyocellular lipid (IMCL) breakdown was enhanced in type I fibers (P < 0.05) and tended to be increased in type IIa fibers (P = 0.07). Training did not affect IMCL breakdown in CHO. In addition, F (+21%) increased the exercise intensity corresponding to the maximal rate of fat oxidation more than did CHO (+6%) (P < 0.05). Furthermore, maximal citrate synthase (+47%) and β-hydroxyacyl coenzyme A dehydrogenase (+34%) activity was significantly upregulated in F (P < 0.05) but not in CHO. Also, only F prevented the development exercise-induced drop in blood glucose concentration (P < 0.05). In conclusion, F is more effective than CHO to increase muscular oxidative capacity and at the same time enhances exercise-induced net IMCL degradation. In addition, F but not CHO prevented drop of blood glucose concentration during fasting exercise. |
| | |
Authors:
|
Karen Van Proeyen; Karolina Szlufcik; Henri Nielens; Monique Ramaekers; Peter Hespel |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-11-04 |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 110 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2011 Jan |
Date Detail:
|
Created Date: 2011-01-13 Completed Date: 2011-08-02 Revised Date: 2012-01-10 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
|
Languages: eng Pagination: 236-45 Citation Subset: IM |
Affiliation:
|
Research Centre for Exercise and Health, Department of Biomedical Kinesiology, K. U. Leuven, Leuven, Belgium. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adaptation, Physiological
/
physiology* Blood Glucose / metabolism* Exercise / physiology* Fasting / physiology* Humans Male Oxygen Consumption / physiology* Physical Endurance / physiology* Physical Fitness / physiology* Young Adult |
| Chemical | |
Reg. No./Substance:
|
0/Blood Glucose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Can rodent longevity studies be both short and powerful?
Next Document: Ventilatory and carotid body chemoreceptor responses to purinergic P2X receptor antagonists in newbo...