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Effects of dead space loading on neuro-muscular and neuro-ventilatory coupling of the respiratory system during exercise in healthy adults: Implications for dyspnea and exercise tolerance
- Source :
-
Respiratory Physiology & Neurobiology . Dec2011, Vol. 179 Issue 2/3, p219-226. 8p. - Publication Year :
- 2011
-
Abstract
- Abstract: We examined the effects of dead space loading (DSL) on ventilation , neural respiratory drive (EMGdi%max, diaphragm EMG expressed as a % of maximal EMGdi), contractile respiratory muscle effort (Pes,tidal%PImax, tidal esophageal pressure swing expressed as a % of maximal inspiratory Pes) and exertional dyspnea intensity ratings in 11 healthy adults with normal spirometry. Subjects completed, in random order, symptom-limited incremental cycle exercise tests under control (CTRL) and DSL (500ml) conditions. Compared with CTRL, DSL decreased exercise tolerance by 20–25%; increased exertional dyspnea intensity ratings in direct proportion to concurrent increases in EMGdi%max, Pes,tidal%PImax and ; and had little/no effect on the inter-relationships between EMGdi%max, Pes,tidal%PImax and during exercise. In conclusion, DSL was associated with an earlier onset of intolerable dyspnea; however, neuro-muscular and neuro-ventilatory coupling of the respiratory system remained relatively preserved during exercise in the presence of an increased external dead space. Under these circumstances, DSL-induced increases in exertional dyspnea intensity ratings reflected, at least in part, the awareness of increased neural respiratory drive, contractile respiratory muscle effort and ventilatory output. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 15699048
- Volume :
- 179
- Issue :
- 2/3
- Database :
- Academic Search Index
- Journal :
- Respiratory Physiology & Neurobiology
- Publication Type :
- Academic Journal
- Accession number :
- 67249450
- Full Text :
- https://doi.org/10.1016/j.resp.2011.08.009