The purpose of this study was to evaluate how physical conditioning is associated with haemostatic and rheological responses to strenuous exercise. A total of 25 males, divided into two groups differing in exercise fitness (14 sedentary and 11 active), underwent exercise testing on a bicycle ergometer with an initial 25 W workload increasing by the same amount every 3 min. The following variables were evaluated before and after the test: platelet count and aggregability, plasma fibrinogen, fibrinolytic degradation products, viscometry and micro-haematocrit. Significant differences in baseline values between the two groups were found only for blood viscosity. Irrespective of the group, significantly increased values were demonstrated for all the variables, except platelet aggregability and fibrinogen levels, in response to strenuous exercise. It is concluded that the possible protective effect of exercise against cardiovascular disease does not seem to be related to changes in the haemorheological and haemostatic measures evaluated.
Scalzi et al. (1987) studied this question.