Lipolytic Markers, Insulin and Resting Fat Oxidation are Associated with Maximal Fat Oxidation.
The maximal capacity to oxidize fat during exercise (MFO) is associated with 24-h fat balance and insulin sensitivity. Understanding factors that influence MFO could have implications for metabolic health. We investigated relationships between selected plasma metabolites, hormones and overnight-fasted resting fat oxidation rates (Resting), with MFO. Resting fat oxidation and MFO was measured in 57 men with blood collected at rest and during exercise. Plasma glycerol (R=0.39, P=0.033), non-esterified fatty acids (NEFA: R=0.27, P=0.030) and insulin (R=- 0.36, P=0.007) measured at MFO correlated with MFO; only glycerol remained correlated when controlled for resting concentrations (R=0.36, P=0.008). The change in glycerol from rest to MFO correlated with exercise-induced fat oxidation (R=0.32, P=0.012). V˙O 2max correlated with resting fat oxidation (R=0.44, P=0.001) and MFO (R=0.52, P<0.001). Resting fat oxidation correlated with MFO (R=0.55, P<0.001); this remained when controlled for V˙O 2max (R=0.41, P=0.001). This study reports weak-to-moderate, albeit significant, relationships between plasma lipolytic markers, insulin and resting overnight-fasted fat oxidation with MFO and shows the plasma glycerol response to uniquely reflect exercise-induced fat oxidation. V˙O 2max correlates with fat oxidation but the relationship can be dissociated. Interventions to increase fat oxidation for optimal metabolic health would benefit from, but are not reliant on, increases in V˙O 2max.
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom of Great Britain and Northern Ireland.
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Robinson
Nutrition and Dietetic Research Group, Imperial College London, London, United Kingdom of Great Britain and Northern Ireland.
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Chambers
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom of Great Britain and Northern Ireland.
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Fletcher
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom of Great Britain and Northern Ireland.
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Wallis
D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005990:Glycerol / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D019344:Lactic Acid / Q000097:blood; D050356:Lipid Metabolism; D008297:Male; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D012146:Rest; D055815:Young Adult
D015415:Biomarkers; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019344:Lactic Acid; D005990:Glycerol