Cardio-respiratory Responses to Exercise: Standard cardio-respiratory measures will be recorded on a breath-by-breath basis and averaged over 30-second epochs, including minute ventilation (V'E), oxygen consumption (VO2), carbon dioxide production (CO2), tidal volume, and breathing frequency using a commercially available metabolic cart. Operating volumes (i.e., end-expiratory and end-inspiratory lung volumes) will be derived from dynamic inspiratory capacity (IC) manoeuvres as previously described. For safety purposes, electrocardiography will be monitored using a 12-lead electrocardiogram (ECG), blood pressure will be measured using a manual sphygmomanometer, and arterial oxygen saturation will be monitored using pulse oximetry. All exercise tests will be administered by experienced exercise physiologists. All exercise tests will be supervised by either Dr. Quon, Dr. Wilcox, Dr. Goodwin or another qualified physician. Exercise tests will be terminated based on established criteria as per American College of Sports Medicine guidelines.