Relationships between hemodynamic, hemorheological and metabolic responses during exercise

Article type: Research Article

Authors: Connes, Philippe^; | Tripette, Julien^; | Mukisi-Mukaza, Martin^; | Baskurt, Oguz K. | Toth, Kalman | Meiselman, Herbert J. | Hue, Olivier | Antoine-Jonville, Sophie

Affiliations: Laboratory ACTES, Département de Physiologie, Université des Antilles et de la Guyane, Campus de Fouillole, Pointe-à- Pitre, Guadeloupe | UMR S 763 Inserm/Université des Antilles et de la Guyane, CHU Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe | Service d'Orthopédie et de Traumatologie, CHU Pointe-à-Pitre/Abymes, Pointe-à-Pitre, Guadeloupe | Department of Physiology, Faculty of Medicine, Akdeniz University, Antalya, Turkey | 1st Department of Medicine, School of Medicine, University of Pécs, Pécs, Hungary | Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA

Note: [] Address for correspondence: Dr. Philippe Connes, Laboratoire ACTES (EA 3596), Département de Physiologie, Université des Antilles et de la Guyane, Campus de Fouillole, 97159 Pointe-à-Pitre, Guadeloupe (French West Indies). E-mail: [email protected].

Abstract: Aerobic performance is dependent on both cardio-respiratory and peripheral factors with hemodynamic parameters playing a major role. However, whether blood rheology might affect aerobic performance through an effect on hemodynamic factors is not known. The aim of the present study was to assess the relationships between hemodynamic, hemorheological and metabolic parameters in response to a sub-maximal cycling exercise protocol consisting of three successive levels of nine min duration (50, 100 and 150 W). Ten young sportsmen participated in the present study. Mean arterial pressure (MAP) was measured manually, with thoracic impedance used to monitor cardiac output (Qc): systemic vascular resistance (SVR) was then calculated. Whole blood viscosity (ηb) was measured and used to calculate systemic vascular hindrance. Hematocrit (Hct) was determined by micro-centrifugation and red blood cell (RBC) deformability (EI) was determined by ecktacytometry. A breath-by-breath gas analyzer was used to measure oxygen uptake (VO2); the Fick equation was used to calculate arterio-venous oxygen difference [(a-v)O2] from VO2 and Qc. All measurements were performed at rest, during exercise and during recovery. Compared to baseline, Qc, MAP, Hct, EI, VO2, and (a-v)O2 increased during exercise. ηb increased above baseline only at 150 W and remained elevated during recovery; the increase in ηb during the last level of exercise was associated with a decrease of SVR and systemic vascular hindrance. There was a significant negative correlation between EI and SVR (r=−0.35, p<0.01) and a significant positive relationship between EI and (a-v)O2 (r=0.35, p<0.01) and between EI and VO2 (r=0.37, p<0.01) across all exercise workloads, thus suggesting a potential role for RBC deformability as a factor affecting aerobic performance via oxygen delivery to tissues. These data lend support to the concept that hemorheological parameters may contribute to hemodynamic and cardio-respiratory adaptations in response to exercise in moderately trained sportsmen.

Keywords: Blood rheology, exercise physiology, hemodynamics, oxygen uptake

DOI: 10.3233/BIR-2009-0529

Journal: Biorheology, vol. 46, no. 2, pp. 133-143, 2009