Walking-induced inertial effects on the cardiovascular system

Area of Science:

• Physiology
• Biomedical Engineering
• Computational Modeling

Background:

• Cardiovascular and locomotor systems interact dynamically during exercise.
• Mechanisms of cardiovascular-locomotor coupling during walking are not fully understood.
• Existing computational models lack the inclusion of inertial forces from body motion.

Purpose of the Study:

• To develop and validate a closed-loop cardiovascular model that incorporates inertial effects during walking.
• To investigate the influence of body motion-induced inertial forces on hemodynamics.
• To enhance understanding of physiological network adaptations to exercise.

Main Methods:

• Developed a 25-compartment lumped parameter cardiovascular model with heart dynamics, pressures, and baroreflex.
• Modeled inertial effects as hydrodynamic pressure sources due to blood mass acceleration.
• Validated the model using head-up tilt tests, synthetic walking simulations, and a human walking experiment.

Main Results:

• The model accurately reproduced physiological responses to head-up tilt.
• Inertial effects during synthetic walking led to pressure augmentation, varying with heart rate and step rate phasing.
• The model successfully replicated beat-wise hemodynamic changes in human subjects, showing improved waveform similarity with inertial effects included.

Conclusions:

• Body acceleration-induced hydrodynamic pressure is a valid method to model walking's inertial effects on hemodynamics.
• This research provides a foundation for studying cardiac-locomotor interactions during exercise.
• The findings contribute to characterizing physiological network adaptations during physical activity.