Fat Oxidation Kinetics Is Related to Muscle Deoxygenation Kinetics During Exercise.

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State: Public
Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_03F44462F9E8
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Fat Oxidation Kinetics Is Related to Muscle Deoxygenation Kinetics During Exercise.
Journal
Frontiers in physiology
Author(s)
Zurbuchen A., Lanzi S., Voirol L., Trindade C.B., Gojanovic B., Kayser B., Bourdillon N., Chenevière X., Malatesta D.
ISSN
1664-042X (Print)
ISSN-L
1664-042X
Publication state
Published
Issued date
2020
Peer-reviewed
Oui
Volume
11
Pages
571
Language
english
Notes
Publication types: Journal Article
Publication Status: epublish
Abstract
The present study aimed to determine whether whole-body fat oxidation and muscle deoxygenation kinetics parameters during exercise were related in individuals with different aerobic fitness levels.
Eleven cyclists [peak oxygen uptake ( ): 64.9 ± 3.9 mL⋅kg <sup>-1</sup> ⋅min <sup>-1</sup> ] and 11 active individuals ( : 49.1 ± 7.4 mL⋅kg <sup>-1</sup> ⋅min <sup>-1</sup> ) performed a maximal incremental cycling test to determine and a submaximal incremental cycling test to assess whole-body fat oxidation using indirect calorimetry and muscle deoxygenation kinetics of the vastus lateralis (VL) using near-infrared spectroscopy (NIRS). A sinusoidal (SIN) model was used to characterize fat oxidation kinetics and to determine the intensity (Fat <sub>max</sub> ) eliciting maximal fat oxidation (MFO). The muscle deoxygenation response was fitted with a double linear model. The slope of the first parts of the kinetics (a <sub>1</sub> ) and the breakpoint ([HHb] <sub>BP</sub> ) were determined.
MFO (p = 0.01) and absolute fat oxidation rates between 20 and 65% were higher in cyclists than in active participants (p < 0.05), while Fat <sub>max</sub> occurred at a higher absolute exercise intensity (p = 0.01). a <sub>1</sub> was lower in cyclists (p = 0.02) and [HHb] <sub>BP</sub> occurred at a higher absolute intensity (p < 0.001) than in active individuals. was strongly correlated with MFO, Fat <sub>max</sub> , and [HHb] <sub>BP</sub> (r = 0.65-0.88, p ≤ 0.001). MFO and Fat <sub>max</sub> were both correlated with [HHb] <sub>BP</sub> (r = 0.66, p = 0.01 and r = 0.68, p < 0.001, respectively) and tended to be negatively correlated with a <sub>1</sub> (r = -0.41, p = 0.06 for both).
This study showed that whole-body fat oxidation and muscle deoxygenation kinetics were both related to aerobic fitness and that a relationship between the two kinetics exists. Individuals with greater aerobic fitness may have a delayed reliance on glycolytic metabolism at higher exercise intensities because of a longer maintained balance between O <sub>2</sub> delivery and consumption supporting higher fat oxidation rates.
Keywords
Physiology (medical), Physiology, Fatmax, NIRS, aerobic fitness, breaking point, cycling, indirect calorimetry
Pubmed
Web of science
Open Access
Yes
Create date
04/06/2020 9:38
Last modification date
28/08/2020 9:07
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