Larsen, Mads Rosenkilde5; Reichkendler, M H5; Auerbach, P5; Bonne, Thomas Christian6; Sjödin, Anders Mikael7; Ploug, Thorkil5; Stallknecht, B M5
1 Section of Systems Biology Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet2 PhD, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet3 Obesity Research, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet4 Department of Exercise and Sport Sciences, Faculty of Science, Københavns Universitet5 Section of Systems Biology Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet6 Department of Exercise and Sport Sciences, Faculty of Science, Københavns Universitet7 Obesity Research, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet
The effect of different doses of endurance training on the capacity to oxidize fat during exercise in sedentary, overweight men and assessment of variables associated with changes in peak fat oxidation (PFO) were evaluated. Young, sedentary, overweight men were randomized to either the high-dose (HIGH, 600 kcal/day, n = 17) or moderate-dose (MOD, 300 kcal/day, n = 18) endurance training groups or controls (CON, n = 15). PFO and peak oxygen uptake (VO2 peak) were measured using indirect calorimetry, body composition using dual-energy x-ray absorptiometry, and protein levels of mitochondrial enzymes determined by Western blotting. PFO increased in both MOD [1.2 mg/kg fat-free mass (FFM)/min, 95% confidence interval (CI): 0.08:2.3, P = 0.03] and HIGH (1.8 mg/kg FFM/min, CI: 0.6:2.9, P < 0.001) compared with CON. Skeletal muscle expression of citrate synthase, β-hydroxyacyl-CoA dehydrogenase, and mitochondrial oxphos complexes II-V increased similarly in MOD and HIGH. Stepwise multiple linear regression analysis with backward elimination of individual variables correlated with changes in PFO revealed increases in cycling efficiency, FFM, and VO2 peak as the remaining associated variables. In conclusion, PFO during exercise increased with both moderate- and high-dose endurance training. Increases in PFO were mainly predicted by changes in VO2 peak, FFM, and cycling efficiency, and less with skeletal muscle mitochondrial enzymes.
Scandinavian Journal of Medicine and Science in Sports, 2015, Vol 25, Issue 1, p. 41-52