Lipolytic Markers, Insulin and Resting Fat Oxidation are Associated with Maximal Fat Oxidation

Abstract

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.

Effect of New Zealand Blackcurrant Extract on Physiological Responses at Rest and during Brisk Walking in Southeast Asian Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

“…We observed in Southeast Asian men, in both the placebo and blackcurrant conditions, that whole-body fat oxidation at rest and during a 30-min brisk walk had significant correlation coefficients of 0.68 and 0.67. As far as we know, the study by Robinson et al [ 27 ] reported for the first time that whole-body fat oxidation at rest and exercise-induced maximal fat oxidation were significantly correlated ( r = 0.55) in healthy, recreationally active Caucasian men ( n = 57). Our value for whole-body fat oxidation at rest (0.06 ± 0.03 g·min −1 ) was somewhat lower than that of Robinson et al [ 27 ] (0.08 ± 0.03 g·min −1 ).…”

“…For the present study, it was hypothesised that New Zealand blackcurrant extract will increase cardiac output at rest and increase fat oxidation during the brisk treadmill walk. It was observed by Robinson et al [ 27 ] in Caucasians that resting fat oxidation correlated significantly with exercise-induced maximal fat oxidation. Therefore, the second aim of the study was to examine whether such a significant correlation exists between whole-body fat oxidation at rest and during brisk walking in Southeast Asian men.…”

Reduced Fat Oxidation During Exercise in Post-Menopausal Overweight-Obese Women with Higher Lipid Accumulation Product Index

“…Obesity-related metabolic disorders impair whole body and skeletal muscle fatty acid oxidation during fasted state, under postabsorptive conditions or physical exercise [2,16,17]. Moreover, low fat oxidation rate at rest is a predictor for weight gain and is involved with the development of insulin resistance in obese and non-obese individuals [18,19].…”

“…Despite the lack of studies evaluating the fat oxidation rate during exercise in MHO and MUO post-menopausal women, there are reports indicating a positive correlation between insulin sensitivity, a marker of metabolic healthy, and MFO in healthy lean and obese young men [17,20]. Moreover, diabetic obese men had decreased MFO and muscle mitochondrial activity than non-diabetic men, suggesting a possible protective role of fat oxidation against insulin resistance and type 2 diabetes [21].…”

Determination of the exercise intensity that elicits maximal fat oxidation in individuals with obesity

“…Albeit weak, resting concentration of plasma FFA (r=-0.53, p<0.05) (Rosenkilde et al 2010), and levels of plasma FFA and glycerol during exercise at Fat Max (r=0.27, p=0.03, r=0.39, p=0.03) correlated with MFO (Robinson et al 2016). Thus, measuring availability of plasma metabolites such as plasma FFA and glycerol seem relevant in studies investigating validity and reliability of Fat Max and MFO.…”