title: The effects of respiratory muscle training on respiratory mechanics and energy cost.
abstract: Resistance respiratory muscle training (RRMT) increases respiratory muscle strength and can increase swimming endurance time by as much as 85%. The purpose of this study was to examine potential mechanisms by which RRMT improves exercise endurance. Eight healthy adult male scuba divers underwent experiments in a hyperbaric chamber at sea level (1 atmosphere absolute (ATA)), 2.7 ATA and 4.6 ATA, both dry and fully submersed. Subjects rested, exercised, and rested while mimicking their own exercise breathing (ISEV). Airway resistance (R(aw)), exhaled nitric oxide output (V˙(NO)), and respiratory duty cycle (T(I)/T(Tot)) were determined before and after four weeks of RRMT. RRMT decreased T(I)/T(Tot) (-10% at rest at 1 ATA), V˙(O2) (-17% at 2.7 ATA during submersed exercise), V˙(E) (-6% at 2.7 ATA during submersed exercise), and R(aw) (-34% inspiratory at 4.6 ATA submersed, -38% expiratory at 2.7 ATA dry), independent of changes in V˙(NO). Most importantly, respiratory muscle efficiency increased (+83% at 2.7 ATA submersed).
authors.affiliation: Center for Research and Education in Special Environments, Department of Physiology and Biophysics, State University of New York at Buffalo, 16 Sherman Annex, Buffalo, NY 14260, United States. Electronic address: hheld1@health.usf.edu.
authors.forename: Heather E
authors.initials: HE
authors.lastname: Held
authors.affiliation: Center for Research and Education in Special Environments, Department of Physiology and Biophysics, State University of New York at Buffalo, 16 Sherman Annex, Buffalo, NY 14260, United States.
authors.forename: David R
authors.initials: DR
authors.lastname: Pendergast
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D001945:Breathing Exercises / Q000379:methods*; D004242:Diving / Q000502:physiology*; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D011312:Pressure; D011650:Pulmonary Alveoli / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000502:physiology*; D012146:Rest / Q000502:physiology; D016896:Treatment Outcome
chemical_list: D009569:Nitric Oxide
keywords: Exercise; Hyperbaric; Immersion; Oxygen consumption; Respiration