Respiratory Minute Volume in Health and Disease
Minute ventilation (or pulmonary ventilation, or respiratory minute volume, or flow of air) is the volume of air that can be inhaled (inhaled minute volume) or exhaled during one minute.
The calculation of minute ventilation is simple: MV=TV*Rf or minute volume is equal to tidal volume (amount of air for one breath, ml) multiplied by the respiratory frequency (number of breaths per minute).
This table shows normal minute ventilation (liters of air per minute) in healthy subjects at rest (14 studies).
Table. Normal respiratory minute volume (healthy subjects only)
*Each row corresponds to a research paper or medical science article
|Condition||Minute ventilation||N. of subjects||References|
|Normal breathing||6 l/min||-||Medical textbooks|
|Healthy subjects||7.7 +- 0.3 l/min||19||Douglas et al, 1982|
|Healthy males||8.4 +- 1.3 l/min||10||Burki, 1984|
|Healthy males||6.3 l/min||10||Smits et al, 1987|
|Healthy males||6.1 +-1.4 l/min||6||Fuller et al, 1987|
|Healthy subjects||6.1 +- 0.9 l/min||9||Tanaka et al, 1988|
|Healthy students||7.0 +- 1.0 l/min||10||Turley et al, 1993|
|Healthy subjects||6.6 +- 0.6 l/min||10||Bengtsson et al, 1994|
|Healthy subjects||7.0 +-1.2 l/min||12||Sherman et al, 1996|
|Healthy subjects||7.0+-1.2 l/min||10||Bell et al, 1996|
|Healthy subjects||6 +- 1 l/min||7||Parreira et al, 1997|
|Healthy subjects||7.0 +- 1.1 l/min||14||Mancini et al, 1999|
|Healthy subjects||6.6 +- 1.1 l/min||40||Pinna et al, 2006|
|Healthy subjects||6.7 +- 0.5 l/min||17||Pathak et al, 2006|
|Healthy subjects||6.7 +- 0.3 l/min||14||Gujic et al, 2007|
|"Normal" subjects||12 +- 2 l/min||>500||Results of 18 studies|
You can find references to these studies on healthy subjects here.
These research papers and medical science articles show that healthy subjects have a very light and easy breathing. For details related pattern at rest, generally corresponding to about 6-7 liters of air per min for their normal minute ventilation values. Modern medical and physiological textbooks provide values for the normal pulmonary ventilation, ranging from 6 up to 9 liters of air per minute at rest for a 70-kg man.
However, it is clear that when the MV is higher than 10 L/min, this is hyperventilation.
Normal ventilation leads to high (or normal) CO2 in the arterial blood and body cells. As a result, O2 transport is normal and they have normal oxygen values in the brain, heart and other body organs and cells.
Minute volume in normal subjects
Pulmonary ventilation values for modern "normal subjects" are much higher, averaging at about 12 L/min.
Respiratory minute volume in people with chronic conditions
What do we know about minute ventilation rates in people with chronic diseases?
Ideal pulmonary ventilation
If we imagine different automatic breathing patterns with different respiratory volume, we can find such a pattern that provides maximum body oxygen levels. We already know that overbreathing reduces body oxygenation due to vasoconstriction, and possibly due to the Bohr effect. However, one can breathe even slower and less than the medical norm for breathing at rest. How much less? You can find out the number X for the respiratory volume that maximizes oxygen levels in the human body. This number X is provided below as your bonus content.
- Respiratory minute volume (From Wikipedia.org)
- Respiratory minute volume (From ScienceDirect.com)
- A Brief Discussion on Minute Ventilation (From DarylConant.com)
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