The Effects of Exercise Training on Resting Prostacyclin and Thromboxane A2 in Older Adults

Abstract

Ten adult volunteers participated in Id weeks of cardiovascular exercise training (EG) to determine the effects of training on resting prostacyclin (PGI2) and thromboxane A2 (TXA2). Six volunteers of similar age served as sedentary controls (CG). Blood was collected in tubes after training and eicosanoids were measured by standard 125I RIA methods. Over the 16 weeks of the study, PGI2 decreased 48% for EG and 33% for CG. There were no between-group differences for PGI2 values. No significant within-group changes in TXA2 were found, whereas between-group pretraining TXA2 values were significantly different. A time main effect for PGI2 may indicate a seasonal shift in this eicosanoid: however, the additional 15% decrease in PGI2 for EG may be due to a training-induced reduction in PGI2 substrate and/or endothelial sensitivity to agonists. The lack of within-group changes in TXA2 may be due to a combination of high platelet turnover and a training stimulus inadequate to alter platelet function.