Affiliations: [a] U1046 INSERM, UMR 9214 CNRS « Physiopathologie & Médecine Expérimentale du Cœur et des Muscles – PHYMEDEXP », Unité d’Explorations Métaboliques (CERAMM), Université de Montpellier, Département de Physiologie Clinique, Hôpital Lapeyronie CHRU Montpellier, France
| [b] Institut des Biomolécules Max Mousseron (IBMM) UMR CNRS 5247, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, France
| [c] Laboratoire de Biophysique & Bio-Analyses, Faculté de Pharmacie, Université de Montpellier, France
| [d] UMR QualiSud, Faculté de Pharmacie, Université de Montpellier, France
Correspondence:
[*]
Corresponding author: Jean-Frédéric Brun,
U1046 INSERM, UMR 9214 CNRS ⪡ Physiopathologie & Médecine Expérimentale du Cœur et des Muscles – PHYMEDEXP ⪢,
Unité d’Explorations Métaboliques (CERAMM), Université de Montpellier, Département de Physiologie Clinique, Hôpital Lapeyronie CHRU Montpellier, France.
E-mail: [email protected].
Abstract: The ideal hematocrit is the hematocrit (Hct) value resulting in the highest value of Hct/viscosity (h/η) ratio and can thus be predicted from viscometric measurements with the use of equations such as Quemada’s one which yield the determination of the bell-shaped curve of h/η as a function of Hct. In a series of recent papers we applied this approach to various populations, using viscometry at high shear rate (1000 s–1). However the shape of this curve has been reported to be dependent on the shear rate, resulting in a right-shift in this top value when Hct increase. We present here in 11 young recreative athletes the evolution of the predicted top of the h/η curve and optimal theoretical Hct and the discrepancy between theoretical and optimal values over the range of shear rates 1 to 6000 s–1. Results show that the predicted optimal value of both h/η and Hct increases when shear rate increases and that the discrepancy between predicted laquooptimalraquo and actual values decreases and becomes almost asymptotic at very high shear (500 s–1). It is minimal at 2720 s–1. The correlation between predicted laquooptimalraquo and actual values of both parameters describes the same evolution. Therefore, it is better for assessing h/η and its agreement with theoretical values, and for determining the theoretical ideal hematocrit, to measure blood viscosity at shear rates equal or superior to 500 s–1.
Keywords: Blood viscosity, hematocrit, hematocrit/viscosity ratio, oxygen delivery
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