The purpose of this study was to confirm the anti-atherogenic effect of exercise on serum lipids. The influence of a triathlon race, as a model to reveal the acute effects of strenuous exercise, on lipid metabolism was examined. 93 Japanese athletes (74 men, 19 women) were studied to determine changes in serum lipids after the Ironman Triathlon race in Kona, Hawaii.
　Significant decreases of triglyceride (TG) and total cholesterol (T-C), significant increases of high density lipoprotein cholesterol (HDL-C) and high density lipoprotein 2 cholesterol (HDL₂-C) were observed after the race in men, just as the results reported for the chronic effects of exercise. These alterations account for the activation of LPL in muscle tissue by exercise. But in women, these changes were not as clear. We assumed the cause of such results in women was due to the lack of activation of LPL by exercise. The sex difference in this activation of LPL by exercise, we asumed, was likely related to lower levels of testosterone in serum in women.
　Increased HDL through strenuous exercise such as in a triathlon was rich in TG ; besides, apolipoprotein A I and apolipoprotein AII, main apolipoproteins of HDL, decreased 1 day after the race. Furthermore, we observed the decrease in lecithin:cholesterol acyltransferase (LCAT) activity after the race. These results suggest that this HDL was partly likely to lack anti-atherogenesity.
　We consider that we have to investigate whether these changes are the same as the changes in the chronic effect of exercise or not. Also to examine not only the change in serum HDL-C or HDL₂-C levels but also the functional change of each lipoprotein. From this point of view, we need to make clear how much exercise or which exercise is the most beneficial to us.

DESCENTE SPORTS SCIENCE Vol.11/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE