title: Target-flow inspiratory muscle training: breathing patterns and metabolic costs.
abstract: In target-flow inspiratory muscle training (TF-IMT), the generated inspiratory mouth pressure and the duration of the inspiration and expiration are standardized to given an adequate training stimulus to the inspiratory muscles. The acute effects of TF-IMT on the efficiency of breathing were studied in a group of 12 COPD patients with a ventilatory limitation of their exercise capacity (mean age 58, mean FEV1 46.2% of predicted) and in 15 normal subjects (mean age 30). Also, the effect of a 10 week period of TF-IMT on the maximal inspiratory mouth pressure (PImax) in the COPD patients was measured. After an unloaded baseline period, the subjects started to inspire through a target-flow device during 15 min, followed by a recovery phase of 5 min. During TF-IMT minute ventilation (VE) decreased only in the COPD group. The ventilatory equivalent for O2 (VE/VO2) and the dead space to tidal volume ratio (VD/VT) decreased in both groups. During recovery, VE, VE/VO2 and VD/VT remained below baseline values in the COPD group, but not in the control group. PCO2 and lactate concentrations did not change during TF-IMT. After the 10 week training period, PImax [means) (SD] increased from 5.7(2.2) to 8.2(2.7) kPa (p less than 0.05). The results indicate that with standardized TF-IMT, the inspiratory muscles can be trained effectively in COPD patients with a ventilatory limitation. The persistence of the decrease in VE, VE/VO2 and VD/VT after a training session may be an additional beneficial effect of TF-IMT.
authors.affiliation: University of Nijmegen, The Netherlands.
authors.forename: P N
authors.initials: PN
authors.lastname: Dekhuijzen
authors.forename: M T
authors.initials: MT
authors.lastname: Hopman
authors.forename: R A
authors.initials: RA
authors.lastname: Binkhorst
authors.forename: H T
authors.initials: HT
authors.lastname: Folgering
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis; D001945:Breathing Exercises; D004734:Energy Metabolism; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008173:Lung Diseases, Obstructive / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000378:metabolism
chemical_list: D007773:Lactates; D019344:Lactic Acid