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Fat oxidation, hormonal and plasma metabolite kinetics during a submaximal incremental test in lean and obese adults.

Lanzi S, Codecasa F, Cornacchia M, Maestrini S, Salvadori A, Brunani A, Malatesta D - PLoS ONE (2014)

Bottom Line: Fat max was 17% significantly lower in O than in L (p<0.01).Fat oxidation kinetics were characterized by similar translation, significantly lower dilatation and left-shift symmetry in O compared with L (p<0.05).Non-esterified fatty acids (NEFA) were significantly higher in O compared with L (p<0.05).

View Article: PubMed Central - PubMed

Affiliation: Institute of Sport Sciences University of Lausanne (ISSUL), University of Lausanne, Lausanne, Switzerland ; Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.

ABSTRACT
This study aimed to compare fat oxidation, hormonal and plasma metabolite kinetics during exercise in lean (L) and obese (O) men. Sixteen L and 16 O men [Body Mass Index (BMI): 22.9 ± 0.3 and 39.0 ± 1.4 kg · m(-2)] performed a submaximal incremental test (Incr) on a cycle-ergometer. Fat oxidation rates (FORs) were determined using indirect calorimetry. A sinusoidal model, including 3 independent variables (dilatation, symmetry, translation), was used to describe fat oxidation kinetics and determine the intensity (Fat(max)) eliciting maximal fat oxidation. Blood samples were drawn for the hormonal and plasma metabolite determination at each step of Incr. FORs (mg · FFM(-1) · min(-1)) were significantly higher from 20 to 30% of peak oxygen uptake (VO2peak) in O than in L and from 65 to 85% VO2peak in L than in O (p ≤ 0.05). FORs were similar in O and in L from 35 to 60% VO2peak. Fat max was 17% significantly lower in O than in L (p<0.01). Fat oxidation kinetics were characterized by similar translation, significantly lower dilatation and left-shift symmetry in O compared with L (p<0.05). During whole exercise, a blunted lipolysis was found in O [lower glycerol/fat mass (FM) in O than in L (p ≤ 0.001)], likely associated with higher insulin concentrations in O than in L (p<0.01). Non-esterified fatty acids (NEFA) were significantly higher in O compared with L (p<0.05). Despite the blunted lipolysis, O presented higher NEFA availability, likely due to larger amounts of FM. Therefore, a lower Fat(max), a left-shifted and less dilated curve and a lower reliance on fat oxidation at high exercise intensities suggest that the difference in the fat oxidation kinetics is likely linked to impaired muscular capacity to oxidize NEFA in O. These results may have important implications for the appropriate exercise intensity prescription in training programs designed to optimize fat oxidation in O.

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Related in: MedlinePlus

Mean non-esterified fatty acid (NEFA) concentrations (A) and mean glycerol concentrations (B) divided by fat mass (C) during the submaximal incremental test in lean (L: blue, n = 16) and obese (O: red, n = 14) individuals.Values are the means±SE. PPO: peak power output. * p≤0.05 for differences with lean; † p≤0.05 for significant group interaction effect.
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pone-0088707-g003: Mean non-esterified fatty acid (NEFA) concentrations (A) and mean glycerol concentrations (B) divided by fat mass (C) during the submaximal incremental test in lean (L: blue, n = 16) and obese (O: red, n = 14) individuals.Values are the means±SE. PPO: peak power output. * p≤0.05 for differences with lean; † p≤0.05 for significant group interaction effect.

Mentions: There were no significant main group and interaction effects for plasma glucose and lactate concentrations (data not shown). Plasma NEFA concentrations showed a significant main group effect (p<0.01) with no significant interaction effect and were significantly higher at Rest and for all exercise intensities in O than in L (Figure 3A, p<0.05). Plasma glycerol concentrations showed a significant interaction effect (p≤0.001) and were significantly higher at Rest and for all exercise intensities in O than in L (Figure 3B, p<0.05). Plasma glycerol concentrations divided by kg of FM were significantly lower at Rest and for all exercise intensities in O than in L [Figure 3C, p≤0.001; significant interaction effect (p≤0.001)].


Fat oxidation, hormonal and plasma metabolite kinetics during a submaximal incremental test in lean and obese adults.

Lanzi S, Codecasa F, Cornacchia M, Maestrini S, Salvadori A, Brunani A, Malatesta D - PLoS ONE (2014)

Mean non-esterified fatty acid (NEFA) concentrations (A) and mean glycerol concentrations (B) divided by fat mass (C) during the submaximal incremental test in lean (L: blue, n = 16) and obese (O: red, n = 14) individuals.Values are the means±SE. PPO: peak power output. * p≤0.05 for differences with lean; † p≤0.05 for significant group interaction effect.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921204&req=5

pone-0088707-g003: Mean non-esterified fatty acid (NEFA) concentrations (A) and mean glycerol concentrations (B) divided by fat mass (C) during the submaximal incremental test in lean (L: blue, n = 16) and obese (O: red, n = 14) individuals.Values are the means±SE. PPO: peak power output. * p≤0.05 for differences with lean; † p≤0.05 for significant group interaction effect.
Mentions: There were no significant main group and interaction effects for plasma glucose and lactate concentrations (data not shown). Plasma NEFA concentrations showed a significant main group effect (p<0.01) with no significant interaction effect and were significantly higher at Rest and for all exercise intensities in O than in L (Figure 3A, p<0.05). Plasma glycerol concentrations showed a significant interaction effect (p≤0.001) and were significantly higher at Rest and for all exercise intensities in O than in L (Figure 3B, p<0.05). Plasma glycerol concentrations divided by kg of FM were significantly lower at Rest and for all exercise intensities in O than in L [Figure 3C, p≤0.001; significant interaction effect (p≤0.001)].

Bottom Line: Fat max was 17% significantly lower in O than in L (p<0.01).Fat oxidation kinetics were characterized by similar translation, significantly lower dilatation and left-shift symmetry in O compared with L (p<0.05).Non-esterified fatty acids (NEFA) were significantly higher in O compared with L (p<0.05).

View Article: PubMed Central - PubMed

Affiliation: Institute of Sport Sciences University of Lausanne (ISSUL), University of Lausanne, Lausanne, Switzerland ; Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.

ABSTRACT
This study aimed to compare fat oxidation, hormonal and plasma metabolite kinetics during exercise in lean (L) and obese (O) men. Sixteen L and 16 O men [Body Mass Index (BMI): 22.9 ± 0.3 and 39.0 ± 1.4 kg · m(-2)] performed a submaximal incremental test (Incr) on a cycle-ergometer. Fat oxidation rates (FORs) were determined using indirect calorimetry. A sinusoidal model, including 3 independent variables (dilatation, symmetry, translation), was used to describe fat oxidation kinetics and determine the intensity (Fat(max)) eliciting maximal fat oxidation. Blood samples were drawn for the hormonal and plasma metabolite determination at each step of Incr. FORs (mg · FFM(-1) · min(-1)) were significantly higher from 20 to 30% of peak oxygen uptake (VO2peak) in O than in L and from 65 to 85% VO2peak in L than in O (p ≤ 0.05). FORs were similar in O and in L from 35 to 60% VO2peak. Fat max was 17% significantly lower in O than in L (p<0.01). Fat oxidation kinetics were characterized by similar translation, significantly lower dilatation and left-shift symmetry in O compared with L (p<0.05). During whole exercise, a blunted lipolysis was found in O [lower glycerol/fat mass (FM) in O than in L (p ≤ 0.001)], likely associated with higher insulin concentrations in O than in L (p<0.01). Non-esterified fatty acids (NEFA) were significantly higher in O compared with L (p<0.05). Despite the blunted lipolysis, O presented higher NEFA availability, likely due to larger amounts of FM. Therefore, a lower Fat(max), a left-shifted and less dilated curve and a lower reliance on fat oxidation at high exercise intensities suggest that the difference in the fat oxidation kinetics is likely linked to impaired muscular capacity to oxidize NEFA in O. These results may have important implications for the appropriate exercise intensity prescription in training programs designed to optimize fat oxidation in O.

Show MeSH
Related in: MedlinePlus