The mechanisms of controlling residual volume and lung emptying in different ages have been examined. Elastic bandage was wrapped around the abdomen, chest and shoulder (chest strapping). The measurements of various lung volumes and airway resistance were performed with and without chest strapping. Reduction in all lung volumes including residual volume (-12%) and light increase in airway resistance were obtained in subjects below 25 years with chest strapping, whereas residual volumes were higher (+ 17%, + 12%) under chest strapping in subjects between 35 and 50 years and > 60 years of age, respectively. The airway resistance was also considerably higher in these two groups. A decrease in residual volume points to the fact that the major controlling mechanism of residual volume lies in the chest wall. Chest strapping removes the outward force on the airways, enhances their closure, and traps more air, which increases residual volume. This means that the limitation of emptying lies in the airways in advanced age (> 34 years).