Endurance training increases fatty acid turnover, but not fat oxidation, in young men

• DOI: 10.1152/jappl.1999.86.6.2097
• Publication Date: 2017-12-22T13:55:22Z
• Authors: Anne L. Friedlander; Gretchen A. Casazza; Michael A. Horning; Anton Usaj; George A. Brooks
• Keywords: Respiratory exchange ratio; Endurance Training; Cycle ergometer; Physical exercise

We examined the effects of exercise intensity and a 10-wk cycle ergometer training program [5 days/wk, 1 h, 75% peak oxygen consumption (V˙o 2 )] on plasma free fatty acid (FFA) flux, total fat oxidation, whole body lipolysis in healthy male subjects ( n= 10; age = 25.6 ± 1.0 yr). Two pretraining trials (45 65% ofV˙o ) two posttraining (same absolute workload, oldV˙o ; same relative newV˙o were performed by using an infusion [1- 13 C]palmitate [1,1,2,3,3- H]glycerol. An additional nine (age 25.4 0.8 yr) treated similarly but infused with H]glycerol not C]palmitate. Subjects studied postabsorptive for 90 min rest h cycling exercise. After training, increasedV˙o 9.4 1.4%. Pretraining, FFA kinetics inversely related to rates appearance (R disappearance d being significantly higher at 45 than 65%V˙o : 8.14 1.28 vs. 6.64 0.46, R 8.03 6.42 0.41 mol ⋅ kg −1 P ≤ 0.05). when measured intensities, increased 8.84 1.1, 8.44 1.1 8.82 8.35 , respectively Total oxidation determined from respiratory exchange ratio was elevated during compared rest, did differ among four conditions. Glycerol demonstrate significant or Thus, young men, flux is after endurance whole-body are unaffected intensities.