Platelet function and plasma catecholamines in healthy volunteers influenced by physical stress

Abstract

Physical stress induces the release of catecholamines. Catecholamines activate platelets. In order to test the effect of physical stress on plasma catecholamine release and on platelet reactivity, thirty healthy students (11 female, 19 male), aged 23 ± 1 years were asked to pass a test route (length: 500 m, including 250 stairs (49.50 m)) within a period of 5 min. These test-persons were neither smokers nor exhibited any regular sporting activities. Platelet reactivity values remained unchanged in 20 of these students. However 10 students showed an increase of platelet reactivity from 1.01 ± 0.21 to 1.73 ± 0.43. Plasma adrenaline was raised in these 10 students by 78 ± 92 pg/ml, whereas plasma adrenaline changed only by 21 ± 26 pg/ml in the remaining 20 test-persons. There was no difference between sex and age of the two groups. The increase in pulse and blood pressure was also identical. The results indicated that an increase in plasma adrenaline under physical stress is not necessarily accompanied by an increase in platelet reactivity. Only in those healthy persons with an abnormally high increase in plasma adrenaline does platelet reactivity also become pathological.

Zusammenfassung

Die Veränderung der Thrombozytenaggregation unter nur geringstem körperlichen Streß scheint ein prinzipielles Problem der in-vitro-Aggregationsmessung zu sein [14]. Im Gegensatz zu Aggregationsverfahren ist die Plättchenreaktivität intraindividuell wesentlich besser reproduzierbar und relativ stabil [8]. Dennoch finden sich bei Patienten mit zerebralen Ischämien erhöhte Werte für die Plättchenreaktivität [6]. Bei diesen Patienten konnte außerdem auffällig häufig eine pathologische Erhöhung der Plasmakatecholaminspiegel beobachtet werden [2]. Untersuchungen von JACOBI [11], LANDE et al. [9] und LEVINE et al. [10] lassen immerhin einen Zusammenhang zwischen Streßhormonkonzentrationen und Plättchenfunktion vermuten. Neben psychischem Streß geht physischer Streß ebenfalls mit einer vermehrten Freisetzung von Katecholaminen einher.