Respiratory Chemosensitivity and Resistive Load Sensation Influences on Ventilatory Control during Exercise
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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This study examined the effect of added inspiratory resistance R1 to determine the relationship between respiratory sensations and hypercapnic responsiveness to exercise breathing patterns and work performance. Mild R1 5 cm H2O l sec did not alter peak oxygen uptake, peak power output, or steady- state submaximal work duration. During progressive intensity exercise, changes in the pattern of breathing occurred with R1 whereas, breathing cycle timing components were relatively unchanged. During the submaximal steady-state exercise, R1 decreased mean inspiratory flow but prolonged the duty cycle thus maintaining minute ventilation. Exercise minute ventilation was strongly correlated to subjects ventilatory hypercapnic responsiveness. Of the components of minute ventilation, timing and respiratory drive, the latter was correlated to hypercapnic responsiveness during both maximal intensity and submaximal exercise. Subjects perception of R1 did affect their pattern of breathing when added inspiratory loads were present, but ventilatory responsiveness to hypercapnia was the stronger determinant of exercise hyperpnea. It may be possible to screen soldiers who are more prone to work performance decrements when wearing a CB mask. Respiratory muscle strength training programs may help alleviate the adverse respiratory sensations experienced by soldiers wearing CB masks.
- Chemical, Biological and Radiological Warfare
- Protective Equipment