title: The effect of huffing and directed coughing on energy expenditure in young asymptomatic subjects.
abstract: Coughing and huffing have been shown to be effective airway clearance techniques and some authors have anecdotally reported that a huff requires less energy than a series of coughs commencing and finishing at the same lung volume. The aim of this study was to determine whether there is a difference in the energy expenditure between periods of huffing and directed voluntary coughing commencing from the same initial lung volume in young asymptomatic subjects. Energy expenditure was measured using open-circuit indirect calorimetry equipment. Twenty-four non-smoking asymptomatic subjects (12 male, 12 female, aged 18-24 years), without any form of disease and within 10% of their predicted pulmonary function, completed the study. Energy expenditure was measured over three 10min, randomly ordered sessions of huffing, directed coughing and rest. The forced expiratory sessions comprised a single huff or double-barrel cough (both starting at total lung capacity) at the end of every two minutes. Each session was separated by a 5min washout period. No significant difference in energy expenditure was found between the huffing and directed coughing periods (mean difference 0.003 mL/kg/min (95% CI -0.160 to 0.114) and both produced significantly greater energy expenditure than rest (rest and huff mean difference 0.309 mL/kg/min (95% CI 0.080 to 0.549) and rest and cough mean difference 0.306 mL/kg/min (95% CI 0.074 to 0.508)). The suggested benefits of huffing versus coughing in terms of energy conservation are yet to be shown.
authors.affiliation: University of South Australia, Adelaide, Australia.
authors.forename: Edward
authors.initials: E
authors.lastname: Pontifex
authors.forename: Marie T
authors.initials: MT
authors.lastname: Williams
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lunn
authors.forename: David
authors.initials: D
authors.lastname: Parsons
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003371:Cough / Q000503:physiopathology*; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D012120:Respiration Disorders / Q000503:physiopathology; D015656:Respiratory Mechanics