Skip to main content
Article
Fat oxidation over a range of exercise intensities: fitness versus fatness
Applied Physiology, Nutrition, and Metabolism
  • Ilaria Croci, The University of Queensland
  • Ingrid Hickman, The University of Queensland
  • Rachel Wood, Queensland University of Technology
  • Fabio Borrani, University of Lausanne
  • Graeme Macdonald, The University of Queensland
  • Nuala Byrne, Bond University
Date of this Version
1-1-2014
Document Type
Journal Article
Publication Details

Citation only

Fat oxidation over a range of exercise intensities: Fitness versus fatness. (2014). Applied Physiology, Nutrition, and Metabolism, 39(12), 1352-1359.

Access the journal

© Copyright, The Authors, 2014

Abstract
Maximal fat oxidation (MFO), as well as the exercise intensity at which it occurs (Fatmax), have been reported as lower in sedentary overweight individuals but have not been studied in trained overweight individuals. The aim of this study was to compare Fatmax and MFO in lean and overweight recreationally trained males matched for cardiorespiratory fitness (CRF) and to study the relationships between these variables, anthropometric characteristics, and CRF. Twelve recreationally trained overweight (high fatness (HiFat) group, 30.0% ± 5.3% body fat) and 12 lean males (low fatness (LoFat), 17.2% ± 5.7% body fat) matched for CRF (maximal oxygen consumption (V̇O2max) 39.0 ± 5.5 vs. 41.4 ± 7.6 mL·kg(-1)·min(-1), p = 0.31) and age (p = 0.93) performed a graded exercise test on a cycle ergometer. V̇O2max and fat and carbohydrate oxidation rates were determined using indirect calorimetry; Fatmax and MFO were determined with a mathematical model (SIN); and % body fat was assessed by air displacement plethysmography. MFO (0.38 ± 0.19 vs. 0.42 ± 0.16 g·min(-1), p = 0.58), Fatmax (46.7% ± 8.6% vs. 45.4% ± 7.2% V̇O2max, p = 0.71), and fat oxidation rates over a wide range of exercise intensities were not significantly different (p > 0.05) between HiFat and LoFat groups. In the overall cohort (n = 24), MFO and Fatmax were correlated with V̇O2max (r = 0.46, p = 0.02; r = 0.61, p = 0.002) but not with % body fat or body mass index (p > 0.05). Fat oxidation during exercise was similar in recreationally trained overweight and lean males matched for CRF. Consistently, substrate oxidation rates during exercise were not related to adiposity (% body fat) but were related to CRF. The benefits of high CRF independent of body weight and % body fat should be further highlighted in the management of obesity.
Citation Information
Ilaria Croci, Ingrid Hickman, Rachel Wood, Fabio Borrani, et al.. "Fat oxidation over a range of exercise intensities: fitness versus fatness" Applied Physiology, Nutrition, and Metabolism (2014) ISSN: 1715-5312
Available at: http://works.bepress.com/nuala_byrne/26/