The threshold for sensing airflow resistance during tidal breathing rises in old age: implications for elderly patients with obstructive airways diseases.

OBJECTIVE to determine whether the ability of elderly subjects to detect a rise in airflow resistance is attenuated in old age, and to measure the magnitude and variability of such a change. METHODS we studied 124 healthy adults aged 20-86 years. Progressive external airflow resistance loading was used to measure the inspiratory and expiratory load detection thresholds (LDTs) during tidal breathing at rest. RESULTS the mean inspiratory LDT rose from 4.00 (3.06 SD) kPa.s/L in the 20-39 age group to 6.51 (6.20) in the 40-64 age group (NS) and 29.10 (13.58) in the 65 + age group (P < 0.00001). The inspiratory LDT was significantly correlated with age, mainly due to the higher thresholds in people over the age of 65 (r = 0.7860, P < 0.00001), but did not correlate with age-corrected forced vital capacity or respiratory rate. Expiratory LDT values and correlations were very similar. Day-to-day variability in LDTs tended to be higher in older subjects. CONCLUSION the threshold for detecting external resistive loads during tidal breathing rises in old age. This appears to be a consequence of ageing processes rather than pathology, and might be a manifestation of a fall in proprioceptive acuity in elderly people. This finding has clinical implications for the self-management of asthma in old age. There is a need to conduct a similar study in patients with airways disease.