Influence of different preceding exercises on fat metabolism during subsequent endurance exercise

BACKGROUND: Preceding exercise enhances fat metabolism during subsequent endurance exercise. However, it is unknown which type of exercise most enhances fat metabolism during subsequent exercise. The aim of this study was to examine the influence of preceding resistance or endurance exercise on fat metabolism during subsequent endurance exercise and to compare the effect with that without a preceding exercise. METHODS: Nine male subjects performed the following trials: 1) endurance exercise (E trial), 2) endurance exercise preceded by resistance exercise (R+E trial), and 3) endurance exercise preceded by endurance exercise (E+E trial). There was a 20-min break after the preceding exercise. Subsequent endurance exercise was performed on a cycle ergometer at 80% of the individual ventilatory threshold. Blood and exhaled gas were analyzed respectively. RESULTS: The R+E and E+E trials showed a significantly lower respiratory exchange ratio (RER) and a higher amount of fat oxidation during endurance exercise than those in the E trial (P<0.05). Furthermore, the E+E trial showed a significantly lower RER (0.86±0.03 vs. 0.84±0.02) and a significantly higher amount of fat oxidation (0.38±0.05 g/min vs. 0.44±0.08 g/min) than those in the R+E trial. CONCLUSIONS: This study suggested that fat oxidation during subsequent endurance exercise was enhanced when a preceding exercise was performed and that endurance exercise as a preceding exercise enhanced fat oxidation more than resistance exercise did.