[Age-dependent mechanical properties of the lung (author's transl)].

Capacity resistance breaking and volume resistance breaking were determined in normal subjects divided into three groups according to their age. There was a statistically significant age dependence with regard to both values. At a higher age, capacity resistance breaking increases in the respiratory tract already above the end-expiratory intrathoracic gas volume. There is a clear-cut age-dependent narrowing of the ventilatory reserve. This points to a relationship to "senile emphysema". It is probable that the premature loss of individual bronchi is a factor in the abnormal clearing mechanism of the elderly lung.