Title: “The Mechanics and Energetics of the Aging Pulmonary System during Exercise”
Thesis Supervisor: Dr. Bill Sheel (Kinesiology)
Committee Members: Dr. Jordan Guenette (Physical Therapy), Dr Don McKenzie (Kinesiology), Jean-Sebastien Blouin (Kinesiology)
Chair: Dr Eli Puterman
Abstract: Normative aging of the respiratory system involves significant structural changes leading to a progressive decline in pulmonary function. These age-related structural changes include: a decrease in lung elastic recoil, airway size, respiratory muscle strength and chest wall compliance. A decline in pulmonary function impairs breathing which is especially critical during exercise or daily physical activity when ventilations are elevated. As a consequence, it is likely that the respiratory muscles demand more of the body’s energy to keep up with the high ventilatory demands. Additionally, biological sex is important when considering respiratory function. Relative to men, women have smaller lungs, and even when matched for lung size, women have smaller large conducting airways. Inherent anatomical sex differences have functional consequences. At a given ventilation, young women have a higher mechanical work of breathing and oxygen cost of breathing during exercise compared to young men. These findings underscore the importance of understanding sex-based differences during aging. If healthy young women are susceptible to pulmonary limitations during exercise, then healthy older women may be even more vulnerable to the normal effects of aging on the pulmonary system. The overall objective of this proposed thesis is to better understand how biological sex and age influences the mechanical and metabolic work of breathing during ambulatory exercise