Abstract
Haemorheological and haematological parameters were studied in venous blood samples
taken from 8 endurance-trained athletes before and after a marathon run. Viscometry
was performed in a 20 µm glass capillary and in a Couette viscometer. Apparent blood
viscosity was lower in the capillary than in the rotational viscometer, but significant
differences between pre- and post-run samples were not observed in either system.
This is presumably due to the absence of changes of haematocrit (pre-run [mean±SD]:
0.453±0.016, post-run: 0.456±0.018). Although protein concentration increased significantly
from 70.8±2.1 g/l (pre-run) to 76.0±3.9 g/l (post-run), the difference of plasma viscosity
was not statistically significant (pre-run: 1.26+0.03cP, post-run: 1.30±0.07cP). In
all samples, plasma viscosity showed a significant positive correlation with total
protein, globulin, albumin, but not with fibrinogen concentration. Cone-plate aggregometry
and a filtration technique were used to evaluate red cell aggregation and deformability,
two determinants of blood rheology which also were not different between pre- and
post-run samples. The absence of viscosity changes in relation to the marathon run
may be due to the relative stability of blood and plasma volume, which can be deduced
from haematological parameters. Alterations of plasma composition (e.g. acidosis or
hyperosmolality) seem to cause only minor, if any, changes of microrheological cell
properties.
Key words
Viscosity - blood rheology - long-term exercise - marathon running - haematocrit -
deformability - aggregation
