Changes In Fat And Carbohydrate Oxidation During Walking And Running Activities

The aim of the study was to investigate the changes in fat and carbohydrate oxidation rates in the same and different activity speed during walking and running. Eleven healthy males participated in this study. The subjects’ individual preferred walk-to-run transition speeds (WRTS) were determined. Each subject covered 1.5 mile distance for four exercise tests; walking (WRTS-W) and running (WRTS-R) tests at WRTS, 2 km.h-1 slower walking than WRTS (WRTS-2) and 2 km.h-1 faster running than WRTS (WRTS+2). The expired air was measured and analyzed breath-by-breath using an automated online system and heart rate was monitored and recorded throughout walking and running tests. Maximal fat oxidation was observed at the WRTS-R activity. Fat oxidation rate was significantly higher in WRTS-R than WRTS-W. Also, carbohydrate oxidation rates were significantly higher in WRTS-W activity than WRTS-2 and WRTS-2 activities. Our results indicate that differences in fat oxidation during running and walking might have been resulted from activity intensity rather than activity mode.