Effects of exercise training and deconditioning on platelet aggregation induced by alternating shear stress in men.

OBJECTIVE

Alternating shear stress, which resembles the flow condition in stenotic arteries, induces platelet aggregation. This study investigated how exercise training and deconditioning influence alternating shear-induced platelet aggregation (ASIPA) and clarify the mechanisms underlying ASIPA.

METHODS AND RESULTS

Thirty healthy male sedentary subjects were randomly divided into control and trained groups. The trained men were trained on a bicycle ergometer at approximately 60% of maximal oxygen consumption for 30 minutes per day, 5 days per week for 8 weeks, and then were deconditioned for 8 weeks. The experimental results indicate the following: (1) short-term strenuous exercise increases the extent of ASIPA and is accompanied by increased the von Willebrand factor (vWF) binding and P-selectin expression on platelets in both the control and trained groups, whereas the enhancement of platelet function decreases after exercise training in trained subjects; (2) at rest and immediately after exercise, ASIPA and the vWF binding and P-selectin expression on platelets are reduced by training, but remain unchanged in the control group; and (3) deconditioning reverses the effects of training on resting and postexercise state.

CONCLUSIONS

Exercise training suppresses the extent of ASIPA, probably by reducing vWF binding to platelets and P-selectin expression on platelets. However, deconditioning reverses the training effects. This investigation shows that exercise training decreases resting and severe exercise-promoted platelet aggregation induced by alternating shear stress (ASIPA); moreover, this effect is accompanied by reduced the von Willebrand factor binding and P-selectin expression on platelets. However, the effects of training on ASIPA are reversed to the pretraining state after deconditioning.