Clotting and fibrinolytic activity change during the 1 h after a submaximal run

Purpose: To determine the changes in clotting and fibrinolytic activity dur ing the I-h period after an acute submaximal exercise at a specific relativ e exercise intensity to ascertain whether during this time there is a great er risk for developing a clot formation or thrombus. Methods: Ten healthy m en reported between 0700 and 1000 h and ran at 70-75% (V)over dotO(2max) or walked at 1.2 mph for 30 min in a random counter-balanced order. Venous bl ood was obtained at rest, immediately after, and every 20 min during the l- h recovery. Results: There were no differences in the resting parameters fo r each treatment. Walking did not alter the activity of any of the measures analyzed compared with rest. Clotting indicators activated partial thrombo plastin time (APTT) was significantly decreased by approximately 2 s and re mained at this level during the l-h recovery, and factor Vm activity was el evated 66% immediately after the run and remained elevated at this level du ring the l-h recovery period. Fibrinolytic indicators, t-PA, and D-dimers w ere significantly increased immediately after the run. However, I-PA demons trated a quadratic negative slope during the l-h recovery time. D-dimers re mained elevated during the l-h recovery time. Conclusions: These results su ggest that running at 70-75% (V)over dotO(2max) resulted in elevated clotti ng and fibrinolytic activity. However, the clotting activity was sustained during a time when fibrinolytic activity declined, which suggests a more fa vorable situation for clot formation during this time after exercise.