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[RC] LA/ Erythrocytes - Ridecamp GuestPlease Reply to: ti Tivers@xxxxxxx or ridecamp@xxxxxxxxxxxxx ========================================== In this study, fitness improved Erythrocyte Deformability in the presence of lactic acid. Erythrocytes are red cells and they must be able to bend as they go through small blood vessels. On the occasion where the equine spleen has contracted and lactic acid is being produced, fitness plays an important role in preventing a number of problems, possibly bleeding in the lungs, cartilage destruction, tendon damage, muscle damage--caused by inflexible red cells. Echinocytes are permanently damaged stiff red cells often seen in large quantity in racehorses. One rheologist thinks this may be due to chronic sequestration in the acid environment of the equine spleen in horses that are stalled but not properly exercised for days on end. This paper, though, talks about a lesser problem--reduced deformability due to the presence of lactic acid. Authors P Connes, D Bouix, G Py, C Prefaut, J Mercier, JF Brun, C Caillaud Title Opposite effects of in vitro lactate on erythrocyte deformability in athletes and untrained subjects Full source Clinical Hemorheology and Microcirculation, 2004, Vol 31, Iss 4, pp 311-318 Exercise transiently increases blood viscosity: however data on red cell deformability in this process remain inconsistent, since studies report either impairment (proportional to blood lactate accumulation), a lack of effect, or even in some cases an improvement. To test whether these inconsistencies may be due to physiological differences among populations studied, we compared the effects of in vitro lactate (2 mM, 4 mM and 10 mM) on erythrocyte rigidity in venous blood drawn at rest in 10 untrained vs 10 aerobically-trained subjects. After adjustment of osmolality and pH and incubation at 37degreesC during 2 minutes, viscometric measurements were performed at 1000 s(-1) with the MT90 (falling ball) viscometer and Dintenfass's 'Tk' was calculated. While at baseline there was no significant difference in Tk between the two groups, it decreased in the aerobically-trained subjects between 2 and 10 mM lactate concentrations (p<0.05) and increased in the untrained group between 2 and 4 mM (p<0.05). Thus, it seems that endurance training influences erythrocyte response to lactate. Lactate impaired erythrocyte deformability in untrained subjects but it (unexpectedly) improved it in trained subjects. This difference may be due to training-induced adaptations in erythrocyte metabolism, possibly including transmembrane transfer via monocarboxylate transporters. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
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