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

Preview

Text s00421-006-0279-5.pdf - Published Version Available under License Publisher holds Copyright. Download (439kB) | Preview

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.

Interest & Impact

Downloads

105 since deposited on 04 Oct 2013
53 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item