Lung Volumes
The average adult takes 12 to 15 breaths a minute.
A breath is one complete respiratory cycle that consists of one inspiration and one expiration.
A spirometer is used to measure the volume of air that moves into and out of the lungs.
Respiratory (pulmonary) volumes are an important aspect of pulmonary function testing because they can provide information about the physical condition of the lungs.
LUNG VOLUMES VALUES
Tidal volume (TV) is the amount of air that can be inhaled and exhaled during one normal (quiet) breathing cycle (about 500 ml for men & women).
Inspiratory reserve volume (IRV) is the amount of air that can be forcibly inhaled beyond a tidal inhalation (about 3,000 ml for men & 2,000 ml for women).
Expiratory reserve volume (ERV) is the amount of air that can be forcibly exhaled beyond a tidal exhalation (about 1200 ml for men & 700 ml for women).
Residual Volume (RV) (see image below)- the amount of air remaining in the lungs after an ERV (= about 1,200 ml in men & women).
Respiratory (lung) capacities (= two or more respiratory volumes added together)
Inspiratory Capacity = TV + IRV
Functional Reserve Capacity = ERV + RV
Vital capacity (see image below) = TV + IRV + ERV
Total Lung Capacity = RV + VC
LUNG VOLUMES DURING EXERCISE
During exercise, tidal volume increases as the depth of breathing increases and the rate of breathing increases too.
RATE OF: up to 40 - 70 breaths per minute
There is a need for more oxygen in and more carbon dioxide out.
The most commonly used measure of respiratory function with exercise is known as VO2 (volume of oxygen uptake).
VO2 refers to the amount of oxygen taken up and used by the body