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Appears in Collections:Faculty of Health Sciences and Sport Journal Articles
Peer Review Status: Refereed
Title: Effects of exercise intensity and altered substrate availability on cardiovascular and metabolic responses to exercise after oral carnitine supplementation in athletes
Authors: Broad, Elizabeth M
Maughan, Ronald J
Galloway, S D
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Keywords: L-carnitine L-tartrate
fat oxidation
carbohydrate oxidation
Issue Date: Oct-2011
Publisher: Human Kinetics Inc
Citation: Broad EM, Maughan RJ & Galloway SD (2011) Effects of exercise intensity and altered substrate availability on cardiovascular and metabolic responses to exercise after oral carnitine supplementation in athletes, International Journal of Sport Nutrition and Exercise Metabolism, 21 (5), pp. 385-397.
Abstract: The effects of 15 d of supplementation with L-carnitine L-tartrate (LC) on metabolic responses to graded-intensity exercise under conditions of altered substrate availability were examined. Fifteen endurance-trained male athletes undertook exercise trials after a 2-d high-carbohydrate diet (60% CHO, 25% fat) at baseline (D0), on Day 14 (D14), and after a single day of high fat intake (15% CHO, 70% fat) on Day 15 (D15) in a double-blind, placebo-controlled, pair-matched design. Treatment consisted of 3 g LC (2 g L-carnitine/d; n = 8) or placebo (P, n = 7) for 15 d. Exercise trials consisted of 80 min of continuous cycling comprising 20-min periods at each of 20%, 40%, 60%, and 80% VO2peak. There was no significant difference between whole-body rates of CHO and fat oxidation at any workload between D0 and D14 trials for either the P or LC group. Both groups displayed increased fat and reduced carbohydrate oxidation between the D14 and D15 trials (p less than .05). During the D15 trial, heart rate (p less than .05 for 20%, 40%, and 60% workloads) and blood glucose concentration (p less than .05 for 40% and 60% workloads) were lower during exercise in the LC group than in P. These responses suggest that LC may induce subtle changes in substrate handling in metabolically active tissues when fatty-acid availability is increased, but it does not affect whole-body substrate utilization during short-duration exercise at the intensities studied.
Type: Journal Article
Rights: Publisher allows this work to be made available in this repository. Published in International Journal of Sport Nutrition and Exercise Metabolism by Human Kinetics with the following policy: The author retains the right to post an electronic version of the finalized article on electronic repositories controlled by the authors’ institution, provided that the electronic version is in PDF or other image capturing format.
Affiliation: Australian Institute of Sport
Loughborough University

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