Lung function, physical training and altitude
A high level of habitual activity stimulates lung growth during childhood through growth hormone, which stimulates tissue development through insulin growth factors. In subjects with highly developed shoulder muscles (weight lifting, rowing, and archery) accessory respiratory muscles can better lift the thorax; on that account total lung capacity and vital capacity are increased. The FEV1 is not affected, so that the FEV1/VC ratio in such subjects is relatively low. In general athletes have ‘normal’ spirometric indices for age and standing height, but they tend to choose an athletic sport which best fits their physique.
People born and raised at altitude (> 3000 m) have larger lung volumes. This is probably due to stimulation of lung growth by hypoxia in the growing child, but may also arise from greater physical activity.
Reference: Cotes JE. Lung Function. Assessment and application in medicine. Ed. 5, Blackwell Scientific Publications, Oxford, 1993.