title: Relationships between hemodynamic, hemorheological and metabolic responses during exercise.
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 (etab) 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)O(2)] from VO(2) and Qc. All measurements were performed at rest, during exercise and during recovery. Compared to baseline, Qc, MAP, Hct, EI, VO(2), and (a-v)O(2) increased during exercise. etab increased above baseline only at 150 W and remained elevated during recovery; the increase in etab 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)O(2) (r=0.35, p<0.01) and between EI and VO(2) (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.
authors.affiliation: Laboratory ACTES, Département de Physiologie, Université des Antilles et de la Guyane, Campus de Fouillole, Pointe-à- Pitre, Guadeloupe. pconnes@yahoo.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Connes
authors.forename: Julien
authors.initials: J
authors.lastname: Tripette
authors.forename: Martin
authors.initials: M
authors.lastname: Mukisi-Mukaza
authors.forename: Oguz K
authors.initials: OK
authors.lastname: Baskurt
authors.forename: Kalman
authors.initials: K
authors.lastname: Toth
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
authors.forename: Olivier
authors.initials: O
authors.lastname: Hue
authors.forename: Sophie
authors.initials: S
authors.lastname: Antoine-Jonville
mesh_terms: D001809:Blood Viscosity / Q000502:physiology; D004907:Erythrocyte Deformability / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D006439:Hemodynamics / Q000502:physiology*; D018056:Hemorheology / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010108:Oxyhemoglobins / Q000378:metabolism; D014655:Vascular Resistance / Q000502:physiology; D055815:Young Adult
chemical_list: D010108:Oxyhemoglobins