Respiratory Resistance Measurements during Exercise Using the Airflow Perturbation Device

摘要

The work of breathing is influenced by the respiratory mechanics that in turn is affected by the activity of a subject. Previous works have indicated that the total respiratory resistance (resistance from the airways, lung tissues, and the chest wall) are significantly lower for about 30 seconds immediately following exercise. The change in resistance can take place either in the inhalation or exhalation direction or both. The Airflow Perturbation Device (APD) helps to non-invasively measure the respiratory resistance during a state of rest or exercise in both inhalation and exhalation directions. The objective of this study was to compare the pre-exercise resistance to resistance during exercise and to post-exercise resistance especially during the transitional states and to document how fast the respiratory resistances change with a change in physical activity. Using the APD, resistance was continuously measured during pre-exercise (rest) for 2.5 minutes followed by exercise for 6 minutes and finally rest again for 3.5 minutes on a total of 10 healthy non-asthmatic adult subjects. Exercise was performed on a bicycle ergometer pedaling at a rate of 50-70 rpm to elicit a heart rate of 70% of predicted maximum heart rate. From the preliminary data, it is noticed that there is a change in total resistance during the transitional states of "rest to exercise" and "exercise to rest". However, the speed and the range of changes were not consistent within the subjects. A thorough statistical analysis of resistance data of all the subjects will provide us with the knowledge on the total changes in respiratory resistance of subjects during transitions, the speed with which the changes occur, as well as repro-ducibility and sensitivity to changes of the APD.