title: The influence of breathing mechanics on the development of the slow component of O2 uptake.
abstract: We examined the influence of operational lung volumes and mean inspiratory flow on the amplitude of the slow component of O₂uptake (V(O)₂(SC) ) during constant-load cycling performed below and above the respiratory compensation threshold (RCT) in young (24±1yr), healthy individuals (n=10). Subjects demonstrated a significantly greater rise in expiratory reserve volume (ERV) and mean inspiratory flow over the V(O)₂(SC) period during exercise performed above compared with below the RCT (P<0.05). Inspiratory reserve volume (IRV) was, on average, smaller for trials performed above relative to below the RCT (P<0.05). The difference in the magnitudes of change in ERV and mean inspiratory flow, but not IRV, were positively correlated with the increase in V(O)₂(SC) amplitude between work rates (R(2)=0.86, P<0.01). These findings suggest that dynamic hyperinflation and mean inspiratory flow (by increasing inspiratory resistive work) contribute to the development of the V(O)₂(SC') , particularly when exercise is performed above the RCT.
authors.affiliation: School of Physiotherapy and Exercise Science, Gold Coast campus, Griffith University, Gold Coast, Queensland 4222, Australia. t.cross@griffith.edu.au
authors.forename: Troy J
authors.initials: TJ
authors.lastname: Cross
authors.forename: Norman R
authors.initials: NR
authors.lastname: Morris
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Haseler
authors.forename: Donald A
authors.initials: DA
authors.lastname: Schneider
authors.forename: Surendran
authors.initials: S
authors.lastname: Sabapathy
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology; D005105:Expiratory Reserve Volume / Q000502:physiology; D005260:Female; D006801:Humans; D008176:Lung Volume Measurements / Q000379:methods; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000378:metabolism*; D012146:Rest / Q000502:physiology; D014939:Work of Breathing / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen