Objective: To compare preexercise with immediate and 24 h postvalues of coagulation parameters in experienced athletes following a single, 42-km marathon run.
Design: Blood samples were taken 18 h before, immediately after, and 24 h after a marathon race from 14 well-trained individuals, and coagulation factors were measured.
Setting: The setting was a 42-km race on a cloudy day in May with an ambient temperature of 22 degrees C.
Subjects: The subjects were fourteen normal healthy individuals (12 men and 2 women) who regularly participated in runs of at least 20 km each week.
Intervention: The subjects all undertook a 42-km marathon run followed by a 24-h rest period and a repeat assessment.
Main outcome measures: Coagulation factors including factor VIII (FVIII) and von Willebrand factor (vWF) were measured, as was the platelet response to aggregating agents. These responses are all considered as primary outcome measures of hypercoagulability and reflect the prethrombotic state.
Results: The hematocrit was not altered immediately after the race, but the platelet count (mean +/- SD) was significantly elevated (p < 0.05) to 322 +/- 54 x 10(9)/L from 256 +/- 70 x 10(9)/L, and the mean platelet size increased by 24 h (p < 0.05). Platelet aggregation in response to epinephrine, adenosine diphosphate, and collagen was decreased by 40%, 15%, and 60%, respectively, at 24 h; the response to ristocetin was only slightly (10%) altered. There was a significant elevation of beta-thromboglobulin in the plasma at the end of the race, and this elevation persisted for 24 h, indicating considerable release from the platelet alpha granules. The effect on platelet function was further demonstrated by a decrease in the quantity of glycoprotein Ib at 24 h, but not immediately after the race. There was an approximately 300% increase in the levels of FVIII, vWF antigen (vWF:Ag), and ristocetin cofactor activity. In addition, the normal vWF:Ag multimer pattern was changed in the samples taken immediately after the race.
Conclusions: The data support the evidence of significant alteration of certain factors that are involved in coagulation following endurance exercise. Increases in FVIII and vWF are also noted in some prethrombotic conditions. The decreased platelet aggregation suggests early activation during the period of exercise.