Fat Oxidation Kinetics Is Related to Muscle Deoxygenation Kinetics During Exercise.
- Zurbuchen A Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
- Lanzi S Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- Voirol L Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- Trindade CB Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- Gojanovic B Sports Medicine Unit, Swiss Olympic Medical Center, Department for Locomotion, Lausanne University Hospital, Lausanne, Switzerland.
- Kayser B Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- Bourdillon N Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- Chenevière X Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
- Malatesta D Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
- 2020-06-26
Published in:
- Frontiers in physiology. - 2020
English
Purpose
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.
Methods
Eleven cyclists [peak oxygen uptake ( ): 64.9 ± 3.9 mL⋅kg-1⋅min-1] and 11 active individuals ( : 49.1 ± 7.4 mL⋅kg-1⋅min-1) 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 (Fatmax) 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 1) and the breakpoint ([HHb]BP) were determined.
Results
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 Fatmax occurred at a higher absolute exercise intensity (p = 0.01). a 1 was lower in cyclists (p = 0.02) and [HHb]BP occurred at a higher absolute intensity (p < 0.001) than in active individuals. was strongly correlated with MFO, Fatmax, and [HHb]BP (r = 0.65-0.88, p ≤ 0.001). MFO and Fatmax were both correlated with [HHb]BP (r = 0.66, p = 0.01 and r = 0.68, p < 0.001, respectively) and tended to be negatively correlated with a 1 (r = -0.41, p = 0.06 for both).
Conclusion
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 O2 delivery and consumption supporting higher fat oxidation rates.
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.
Methods
Eleven cyclists [peak oxygen uptake ( ): 64.9 ± 3.9 mL⋅kg-1⋅min-1] and 11 active individuals ( : 49.1 ± 7.4 mL⋅kg-1⋅min-1) 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 (Fatmax) 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 1) and the breakpoint ([HHb]BP) were determined.
Results
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 Fatmax occurred at a higher absolute exercise intensity (p = 0.01). a 1 was lower in cyclists (p = 0.02) and [HHb]BP occurred at a higher absolute intensity (p < 0.001) than in active individuals. was strongly correlated with MFO, Fatmax, and [HHb]BP (r = 0.65-0.88, p ≤ 0.001). MFO and Fatmax were both correlated with [HHb]BP (r = 0.66, p = 0.01 and r = 0.68, p < 0.001, respectively) and tended to be negatively correlated with a 1 (r = -0.41, p = 0.06 for both).
Conclusion
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 O2 delivery and consumption supporting higher fat oxidation rates.
- Language
-
- English
- Open access status
- gold
- Identifiers
-
- DOI 10.3389/fphys.2020.00571
- PMID 32581846
- Persistent URL
- https://sonar.ch/global/documents/250731
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