Re: what can affect someone's lung capacity

That’s a good question. Lungs are resilient but remarkably complicated organs, and there are many things that can affect their capacity to hold and move air including, but not limited to, exercise, infections, inflammation, and environmental effects.

Most of the different causes have a limited number of effects. Some, like tuberculosis and emphysema, damage tissues in the lungs, reducing volume by destroying the tiny structures that hold and exchange air. Some, like asthma and allergies cause swelling and inflammation, which also reduces volume and constricts paths for air to move in and out. Others, like pneumonia, cause the tissues to leak fluid, filling up the lungs. And some, like cystic fibrosis, change the elasticity of lung tissue so they can’t expand and contract properly.

The American Lung Association has a lot of information about people’s lungs and what can happen to them, including a list of all sorts of conditions you can read up about.