Relationships between hemodynamic, hemorheological and metabolic responses during exercise

Area of Science:

• Exercise Physiology
• Cardiovascular Physiology
• Hemodynamics
• Blood Rheology

Background:

• Aerobic performance relies on cardio-respiratory and peripheral factors, with hemodynamics playing a key role.
• The influence of blood rheology on hemodynamic factors and subsequent aerobic performance remains unclear.

Purpose of the Study:

• To investigate the relationship between hemodynamic, hemorheological, and metabolic parameters during sub-maximal cycling exercise.
• To assess the role of blood rheology, particularly red blood cell deformability, in exercise adaptations.

Main Methods:

• Ten young sportsmen underwent a sub-maximal cycling protocol (50, 100, 150 W).
• Measurements included mean arterial pressure (MAP), cardiac output (Qc), systemic vascular resistance (SVR), whole blood viscosity (etab), hematocrit (Hct), red blood cell (RBC) deformability (EI), and oxygen uptake (VO2).
• Fick equation was used to calculate arterio-venous oxygen difference [(a-v)O2].

Main Results:

• Cardiac output, MAP, Hct, EI, VO2, and (a-v)O2 increased during exercise.
• Whole blood viscosity increased at 150 W and remained elevated during recovery, correlating with decreased SVR.
• Red blood cell deformability showed significant negative correlation with SVR and positive correlations with (a-v)O2 and VO2.

Conclusions:

• Red blood cell deformability may be a crucial factor influencing aerobic performance by impacting oxygen delivery.
• Hemorheological parameters contribute to hemodynamic and cardio-respiratory adaptations during exercise in trained individuals.