During normal, quiet ventilation a very small amount of basal oxygen consumption is required by the pulmonary system.
The amount of energy required by the pulmonary system can be greater during heavy exercise.
How does pathologic conditions of the pulmonary system drastically change the energy requirement for ventilation?
Pulmonary diseases that decrease lung compliance (ex:atelectases, pulmonary edema), decrease chest wall compliance (ex:kyphoscoliosis), increase airway resistance (ex:bronchitis, asthma), or decrease lung recoil (ex:emphysema) can increase the work of breathing so much that one third or more of the total body energy is used for ventilation. Nutrition is important to maintain energy. We supplement oxygen so patients do not have to work so hard to breath