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Changes in peak fat oxidation in response to different doses of endurance training
Author(s) -
Rosenkilde M.,
Reichkendler M. H.,
Auerbach P.,
Bonne T. C.,
Sjödin A.,
Ploug T.,
Stallknecht B. M.
Publication year - 2015
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12151
Subject(s) - endurance training , citrate synthase , medicine , endocrinology , overweight , vo2 max , skeletal muscle , chemistry , incremental exercise , zoology , enzyme , biology , obesity , biochemistry , heart rate , blood pressure
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 ( VO 2 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 VO 2 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 VO 2 peak, FFM , and cycling efficiency, and less with skeletal muscle mitochondrial enzymes.