1. Increase in residual air volume: Residual air is the amount of air, which is left in the lungs after exhalation. If an individual performs regular exercise, his residual air capacity increases in comparison to an individual who does not perform regular exercise.
2. Increase in size of lungs and chest: When a person performs exercise regularly, he requires more amount of O2. He inhales more amount of air during exercise. Consequently, his lungs and chest are exercised. After some period, the size of his lungs and chest increases.
3. Increase in vital air capacity: It is the amount of air which an individual can inhale and exhale with maximum effort. Its capacity varies from 3500 cc to 4500 cc in a normal adult. It is the sum of tidal volume, inspiratory reserve volume and expiratory reserve volume due to regular exercise its capacity increases up 5500 cc.
