1. Pulmonary Diffusion
   1. No change at rest and submax
   2. Increases at maximal exercises because increased in ventilation & increased in lung perfusion
   3. The amount of gas transferred from the alveoli to the capillary blood
2. Pulmonary Ventilation
   1. Pulmonary ventilation increases at maximal exercises due to increased in tidal volume and respiration rate
   2. Slightly increase during rest & submax exercises
   3. Air flows because of pressure differences between the atmosphere and the gases inside the lungs
3. a-vO2 Difference
   1. Training increases a-vO2 difference especially at max work because increased in O2 extraction by tissues and increased in blood distribution
   2. The difference in the oxygen content of the blood between the arterial blood and the venous blood
   3. Indication of how much oxygen is removed from the blood in capillaries as the blood circulates in the body
4. Respiratory Rate
   1. Steady at rest & submax exercises, but increases at maximal exercises
   2. The normal respiration rate for an adult at rest is 12 to 20 breaths per minute while resting is considered abnormal
   3. A respiration rate under 12 or over 25 breaths per miute while resting is considered abnormal
5. Lung Volumes
   1. Vital capacity = maximum amount of air expelled after maximum inspiration
   2. Residual volume = amount of air that remains in the lungs
   3. Tidal volume = amount of air breathed in & out during normal respiration