Intramyocellular lipid stores increase markedly in athletes after 1.5 days lipid supplementation and are utilized during exercise in proportion to their content

Zehnder, Monica; Christ, Emanuel R; Ith, Michael; Acheson, Kevin J; Pouteau, Etienne; Kreis, Roland; Trepp, Roman; Diem, Peter; Boesch, Chris; Décombaz, Jacques (2006). Intramyocellular lipid stores increase markedly in athletes after 1.5 days lipid supplementation and are utilized during exercise in proportion to their content. European journal of applied physiology, 98(4), pp. 341-54. Heidelberg: Springer 10.1007/s00421-006-0279-5

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Intramyocellular lipids (IMCL) and muscle glycogen provide local energy during exercise (EX). The objective of this study was to clarify the role of high versus low IMCL levels at equal initial muscle glycogen on fuel selection during EX. After 3 h of depleting exercise, 11 endurance-trained males consumed in a crossover design a high-carbohydrate (7 g kg(-1) day(-1)) low-fat (0.5 g kg(-1) day(-1)) diet (HC) for 2.5 days or the same diet with 3 g kg(-1) day(-1) more fat provided during the last 1.5 days of diet (four meals; HCF). Respiratory exchange, thigh muscle substrate breakdown by magnetic resonance spectroscopy, and plasma FFA oxidation ([1-(13)C]palmitate) were measured during EX (3 h, 50% W (max)). Pre-EX IMCL concentrations were 55% higher after HCF. IMCL utilization during EX in HCF was threefold greater compared with HC (P < 0.001) and was correlated with aerobic power and highly correlated (P < 0.001) with initial content. Glycogen values and decrements during EX were similar. Whole-body fat oxidation (Fat(ox)) was similar overall and plasma FFA oxidation smaller (P < 0.05) during the first EX hour after HCF. Myocellular fuels contributed 8% more to whole-body energy demands after HCF (P < 0.05) due to IMCL breakdown (27% Fat(ox)). After EX, when both IMCL and glycogen concentrations were again similar across trials, a simulated 20-km time-trial showed no difference in performance between diets. In conclusion, IMCL concentrations can be increased during a glycogen loading diet by consuming additional fat for the last 1.5 days. During subsequent exercise, IMCL decrease in proportion to their initial content, partly in exchange for peripheral fatty acids.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology > DCR Magnetic Resonance Spectroscopy and Methodology (AMSM)
04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Endocrinology, Diabetology and Clinical Nutrition

UniBE Contributor:

Zehnder, Monica; Christ, Emanuel; Ith, Michael; Kreis, Roland; Trepp, Roman Suria; Diem, Peter and Bösch, Christoph Hans

ISSN:

1439-6319

ISBN:

16902796

Publisher:

Springer

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:46

Last Modified:

23 Nov 2017 15:30

Publisher DOI:

10.1007/s00421-006-0279-5

PubMed ID:

16902796

Web of Science ID:

000240980600002

URI:

https://boris.unibe.ch/id/eprint/19064 (FactScience: 1432)

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