Abstract
Effect of a high-fat diet (HF) containing 50% fat by calorie on metabolic responses to swimming exercise at 32°C or 25°C for 30min in rats was investigated. HF produced significant elevations of blood free fatty acid (FFA) and ketone body concentrations at rest. Swimming at 32°C produced similar increases in blood FFA of both a standard diet (SD) and HF groups. Swimming at 25°C caused a greater rise of blood FFA level in SD group, while there were no significant changes in HF group. Blood ketone body concentration showed similar increases at both 32°C and 25°C in SD group, while in the HF group it did not increase at either 3°C2 or 25°C. In the fasting state for 18hr, swimming at 32°C resulted in significant increases in blood FFA levels in both groups, although the extent of increment was smaller in the HF group. Blood ketone body did not increase significantly in both groups. There was a significant positive correlation between blood FFA and ketone body levels when the results were combined at rest and after exercise in both groups in the fed state, while such a relation was not observed in the fasting state. Swimming induced significant increases in blood lactate concentrations, however, the extent of increment was markedly greater in swimming at lower temperatures and in the HF group.
These results suggest that HF is not necessarily favorable for the exercise function because HF feeding causes less increments of blood FFA and ketone bodies and more lactate production in response to exercise.
