Ge. Vanderbrug et al., HEMORHEOLOGICAL RESPONSE TO PROLONGED EXERCISE - NO EFFECTS OF DIFFERENT KINDS OF FEEDINGS, International journal of sports medicine, 16(4), 1995, pp. 231-237
Thirty-one male triathletes performed three experimental trials at one
week intervals, with either a semi-solid or liquid carbohydrate feedi
ng, or a liquid placebo. Exercise consisted of three hours of alternat
ely cycling, running, cycling, and running at 75 % VO(2)max. Venous bl
ood samples were taken before and immediately after the exercise. Visc
ometry was performed with a Contraves LS-30 viscometer and erythrocyte
deformability was measured with the LORCA, a laser diffractometric sy
stem. Exercise caused a significant increase in whole blood and plasma
viscosity, hematocrit, and osmolality, and avery small, but significa
nt decrease in erythrocyte deformability, irrespective of the feedings
consumed. Changes were not related to exercise performance, as define
d by the maximal test time, probably due to a large fluid intake. The
intake of different amounts of carbohydrate had no influence on the he
morheological parameters, probably since water content was equal among
feedings. Erythrocyte deformability changes were small in comparison
with the other hemorheological changes and a correlation between eryth
rocyte deformability and other parameters was absent. This may be due
to erythrocyte properties to counterbalance volume shifts to ensure an
optimal oxygen delivery in the microcirculation.