|Respiratory minute volume (rest ):||6 liters/min|
|Alveolar ventilation (rest):||4.2 liters/min|
|Maximal voluntary ventilation (BTPS):||125-170 liters/min|
|Timed vital capacity:||83% of total in 1 sec; 97% in 3 sec|
|Work of quiet breathing:||0.5 kg-m/min|
|Maximal work of breathing:||10 kg-m/breath|
Minute Ventilation does not equal Alveolar Ventilation! Each minute at rest about 6 liters of air moves in and out of the lungs (e.g. 12 breaths/min X 500 ml/breath) but only about 4 L of fresh air gets down into the alveolar sacs. That air which stays in the bronchus, bronchioles, etc. does not participate in gas exchange - it is termed the Anatomic Dead Space. Thus alveolar ventilation is 12 X (500 Tidal Volume - 150 Anatomic Dead Space) = 4200 ml/min).
During periods of maximal work/effort, maximal voluntary ventilation can increase over 20-fold. This is a far greater increase that the heart can achieve in terms of cardiac output.
Various measures of the rate at which the lungs can be filled or emptied are used. Sometimes these are percentage change in 1, 2, 3 minutes, time to 50%, etc.
Back To Main 546 Index