Effects of Inspiratory Strength Training on the Detection of Inspiratory Loads
Pressure-threshold loads (ΔPT) are inspiratory force-related loads, which contrast with resistive loads (ΔR), are airflow-dependent loads. If detection of respiratory loads is a function of the background load, then pressure-threshold type inspiratory muscle strength training (IMST) would affect the detection of ΔPT but have less effect on detection of ΔR. ΔR and ΔPT detection and ventilatory responses were measured in healthy volunteers. IMST consisted of 4 sets of 6 breaths per day for 4 weeks, at 75% of maximal inspiratory pressure (MIP). MIP increased and a measure of inspiratory dirve, the mouth pressure generated in the initial 100 msec of an occluded inspiration (P0.1), decreased after IMST. IMST significantly increased MIP after 4 weeks of training. IMST did not change ΔR detection threshold and ΔR-breathing pattern. IMST decreased ΔPT detection percent and ΔPT-breathing pattern. Comparing ΔR and ΔPT at the same mouth pressure-generating level, the detection percent was different. We conclude that IMST affects the detection of ΔPT, but not ΔR. These results also suggest that mouth pressure is not the primary determinant of the inspiratory load detection. The significance of these results is that inspiratory pressure generating capacity can be increased by our pressure threshold training and this increase in respiratory muscle strength increases the ability of pulmonary patients to compensate for increased respiratory load and modulates the threshold for detection of changes in pulmonary mechanics.
KeywordsPsychophysics Inspiratory drive Inspiratory muscle P0.1 Detection threshold
This study was supported by a grant from the National Institutes of Health, NHLBI grant number HL47892.
- American Thoracic Society. (1995). Standardization of spirometry 1994 update. American Journal of Respiratory and Critical Care Medicine, 152(3), 1107–1136.Google Scholar
- Davenport, P. W. (2009). Clinical cough I: The urge-to-cough: A respiratory sensation. Handbook of Experimental Pharmacology, (187), 263–276.Google Scholar
- Davenport, P. W., & Revelette, W. R. (1996). Perception of respiratory mechanical events. In L. Adams & A. Guz (Eds.), Respiratory Sensation (pp. 101–124). New York: Marcel Dekker.Google Scholar