EFFECT OF LONG-TERM AEROBIC EXERCISE ON HELIUM-NEON-LASER-INDUCED THROMBOGENESIS IN RAT MESENTERIC ARTERIOLES AND PLATELET-AGGREGATION

We have previously investigated the antithrombotic effect of aerobic e xercise in rat arterioles and venules under conditions of variable exe rcise load. In the present study, rats were subjected to constant exer cise of 90% maximal oxygen uptake for 30 min, 5 times a week for 2, 4, 8 or 18 weeks. Thrombotic tendency was assessed by the He-Ne-laser-in duced thrombus formation method. Platelet aggregation, platelet adhesi on, whole blood clotting time, fibrinogen levels and blood cell count were also measured. The thrombotic tendency in arterioles decreased si gnificantly after 18 weeks training, but not in venules. Thrombotic te ndency increased slightly after 2 weeks training though the difference s were not significant. A significant decrease in collagen-induced pla telet aggregation was observed after 18 weeks training. The results de monstrated that long-term aerobic training decreased the thrombotic te ndency in rat arterioles and that this was partly due to decreased pla telet aggregability.