In human body we breathed through straws to experience that the lungs have a capacity. We all used one thin straw and one thick straws. The thick straw was a lot easier to breath through than the thick. I think so because it lets more air in at once than the thin straw. When I breathed through the thin straw I had to "cheat" a little by breathing through my nose. But when I was breathing through the wide straw I didn't cheat as much. I think that our body breaths faster when we become more active because we need more air to keep us moving.
Picture below is from http://uabnews.blogspot.com/2012/02/uab-doc-on-capital-hill-today-breathing.html