Sensation and control of breathing: a dynamic model

Area of Science:

• Physiology
• Computational Biology
• Respiratory Control

Background:

• Breathing sensations, or dyspnea, are complex and influenced by multiple physiological factors.
• Understanding the control of breathing is crucial for diagnosing and managing respiratory disorders.

Purpose of the Study:

• To develop and validate a dynamic model of the respiratory control system that predicts breathing sensations.
• To investigate the relationship between ventilatory responses and the perception of breathing effort.

Main Methods:

• A dynamic model of the CO2 respiratory control system was proposed, incorporating arterial CO2 levels and respiratory motor commands.
• Simulations were conducted for exercise and CO2 rebreathing experiments, with and without resistive loading.
• The model's predictions for discomfort index, respiratory motor command, ventilation, and arterial CO2 were compared against experimental data.

Main Results:

• The model accurately reproduced experimental data for ventilation, arterial CO2, and respiratory motor command dynamics.
• Perceptual sensitivity to CO2 was significantly correlated with the hypercapnic ventilatory response slope.
• The discomfort index was minimized under certain conditions, but not identified as the primary control principle.

Conclusions:

• Breathing sensations are influenced by both arterial CO2 and respiratory motor commands.
• A strong link exists between ventilatory response characteristics and the perception of breathing effort.
• Breathing sensations may modulate ventilatory responses by altering the output of the automatic respiratory controller.