Effects of exercise training on blood rheology: A meta-analysis

Issue title: Selected Proceedings of the 16th Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM), 18–21 June, 2011, Munich, Germany

Article type: Research Article

Authors: Romain, Ahmed-Jérôme | Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Raynaud de Mauverger, Eric

Affiliations: Laboratoire Epsylon EA4556, Dynamique des capacités humaines et des conduites de santé Montpellier, Montpellier, France | Laboratoire de Biophysique and Bio-Analyses, Faculté de Pharmacie, Université Montpellier I, Montpellier, France | U1046, INSERM, Université Montpellier 1, Université Montpellier 2, Montpellier, France, and CHRU Montpellier, département de Physiologie Clinique, Montpellier, France

Note: [] Corresponding author: Jean-Frédéric Brun, INSERM U1046 $\laquo$ Physiopathologie and Médecine Expérimentale du Cœur et des Muscles $\raquo$, Unité d'Explorations Métaboliques (CERAMM), Service Central de Physiologie Clinique, et Consultation d'Endocrinologie, Hôpital Lapeyronie CHU Montpellier, Montpellier, France. E-mail: j-brun@chu-montpellier.fr

Abstract: Regular exercise has been reported to improve blood rheology, but all the studies investigating this issue included a reduced number of subjects, and thus it was logic to perform a meta-analysis of them in order to better characterize this physiological effect. Research was handed on Medline from 1950 to 2010. Studies were selected if they were in English and if they had one or several of these following outcomes: lactate, blood viscosity, RBC rigidity, hematocrit (%), RBC aggregation, fibrinogen and plasma viscosity. They were also kept if they included exercise in their protocol. Results were computed with the fixed effect model and the weighting method was the inverse variance. 11 studies with 175 people were found and included in this meta-analysis. None of these studies had the whole mentioned outcomes. The meta-analysis shows significant effects on on RBC aggregation (−0.59 CI 95% [−0.72; −0.46]), whole blood viscosity (−0.30 [−0.31; −0.28] p < 0.001) and hematocrit (−0.296%; CI 95% [−0.57; −0.01]). Aggregation, hematocrit and viscosity data showed significant heterogeneity, aggregation I2 = 94.95%, hematocrit I2 = 96.46%, viscosity I2 = 99.25%. RBC aggregation (0.53 CI 95% [0.40; 0.66]). Three studies could be included for an intervention versus control analysis which shows significant effects on hematocrit (−1.06% CI 95% [−1.43; −0.68]) but bot on aggregation, with again a significant heterogeneity (hematocrit I2 = 96.46%). These results confirm that regular exercise decreases hematocrit and RBC aggregation, but the heterogeneity which is evidenced should be pointed out. This heterogeneity will require a new computation taking into account a “random effect” by using a pooling method. In addition, this heterogeneity leads to conclude that more studies are needed to further analyze these effects which are described by a low number of articles, which could explain some of the non-significant results.

Keywords: Training, blood viscosity, RBC rigidity, hematocrit (%), RBC aggregation, fibrinogen, plasma viscosity, meta-analysis

DOI: 10.3233/CH-2011-1469

Journal: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 199-205, 2011