It is not the intent of this publication to. restrict the authority of the joint force. commander (JFC) from organizing the force. and executing the mission in a manner the JFC. deems most appropriate to ensure unity of. effort in the accomplishment of the overall. mission.
Breathing is only one of the processes that delivers oxygen to where it is needed in the body and removes excess carbon dioxide. The next process in this chain of events is the transport of these gases throughout the body by the circulatory system, and then their uptake or release from the respiring cells.
Humans normally breathe approximately 5 to 6 liters of air per minute through the nose when at rest, but use the mouth as the primary passageway for air when ventilation is increased to approximately 20 to 30 liters per minute during exercise. ACE's Essentials of Exercise Science for Fitness Professionals, p. 8.