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

ABSTRACT

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.