The total lung capacity depends on the person's age, weight, sex and the degree of physical activity. For example, females tend to have a 20-25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. Heavy smokers have a drastically lower capacity than nonsmokers.
Lung capacity is also affected by altitude. A person who is born and lives at sea level will have a smaller lung capacity than a person who spends their life at a high altitude. This is because there is less oxygen in the air at altitude, so the lungs gradually expand to process more air. When someone from sea level travels up to the higher parts of the earth (eg. the Andes, Mexico City, Tibet and the Himalayas) they will often develop a condition called altitude sickness because their lungs cannot process enough oxygen for their bodies needs.Factors affecting lung volume