title: Maximal exercise and lactate do not change red blood cell aggregation in well trained athletes.
abstract: Exercise and lactate usually change blood rheology, particularly red blood cell (RBC) deformability. The effect of lactate on RBC aggregation is unknown. The present study tested the in vivo effects of exercise on both lactate and RBC aggregation and the in vitro effects of lactate on RBC aggregation. Thirteen well trained athletes performed a progressive and maximal exercise test during which blood was sampled at rest, at 50% of maximal exercise, and at maximal exercise. RBC aggregation was assessed with the Myrenne aggregometer which gives two indexes of RBC aggregation: "M" (aggregation during stasis after shearing at 600 s(-1)) and "M1" (facilitated aggregation at low shear rate after shearing at 600 s(-1)). A part of the resting blood sample was also reserved to test the in vitro effects of three lactate concentrations (2, 4 and 10 mM). The lactate solutions were described in a previous study (P. Connes, D. Bouix, G. Py, C. Préfaut, J. Mercier, J.F. Brun and C. Caillaud, Opposite effects of in vitro lactate on erythrocyte deformability in athletes and untrained subjects, Clin. Hemorheol. Microcirc. 31 (2004), 311-318). The results demonstrated that M and M1 were unchanged with exercise and lactate. Therefore, lactate is able to change RBC deformability but not RBC aggregation.
authors.affiliation: UPRES EA 3596 (ACTES), Université des Antilles et de la Guyane, Campus de Fouillole, 97159 Pointe-à-Pitre, Guadeloupe. pconnes@yahoo.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Connes
authors.forename: Corinne
authors.initials: C
authors.lastname: Caillaud
authors.forename: Guillaume
authors.initials: G
authors.lastname: Py
authors.forename: Jacques
authors.initials: J
authors.lastname: Mercier
authors.forename: Olivier
authors.initials: O
authors.lastname: Hue
authors.forename: Jean-Frédéric
authors.initials: JF
authors.lastname: Brun
mesh_terms: D000328:Adult; D004903:Erythrocyte Aggregation / Q000187:drug effects / Q000502:physiology*; D004907:Erythrocyte Deformability / Q000187:drug effects; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D019344:Lactic Acid / Q000097:blood* / Q000494:pharmacology; D008297:Male
chemical_list: D019344:Lactic Acid