Lung volumes
Lung volumes and lung capacities refer to the
The average total lung capacity of an adult human male is about 6
Tidal breathing is normal, resting breathing; the tidal volume is the volume of air that is inhaled or exhaled in only a single such breath.
The average human respiratory rate is 30–60 breaths per minute at birth,[2] decreasing to 12–20 breaths per minute in adults.[3]
Factors affecting volumes
Several factors affect lung volumes; some can be controlled, and some cannot be controlled. Lung volumes vary with different people as follows:
Larger volume | Smaller volumes |
---|---|
taller people | shorter people |
people who live at higher altitudes | people who live at lower altitudes |
fit | obese[4] |
A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude. This is because the partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream. In response to higher altitude, the body's diffusing capacity increases in order to process more air. Also, due to the lower environmental air pressure at higher altitudes, the air pressure within the breathing system must be lower in order to inhale; in order to meet this requirement, the thoracic diaphragm has a tendency to lower to a greater extent during inhalation, which in turn causes an increase in lung volume.
When someone living at or near sea level travels to locations at high altitudes (e.g. the
Lung function development is reduced in children who grow up near motorways[5][6] although this seems at least in part reversible.[7] Air pollution exposure affects FEV1 in asthmatics, but also affects FVC and FEV1 in healthy adults even at low concentrations.[8]
Values
Volume | Value (litres) | |
---|---|---|
In men | In women | |
Inspiratory reserve volume (IRV) | 3.3 | 1.9 |
Tidal volume (TV) | 0.5 | 0.5 |
Expiratory reserve volume (ERV) | 1.1 | 0.7 |
Residual volume (RV) | 1.2 | 1.1 |
Volume | Average value (litres) | Derivation | |
---|---|---|---|
In men | In women | ||
Vital capacity | 4.8 | 3.1 | IRV + TV + ERV |
Inspiratory capacity | 3.8 | 2.4 | IRV + TV |
Functional residual capacity | 2.4 | 1.8 | ERV + RV |
Total lung capacity | 6.0 | 4.2 | IRV + TV + ERV + RV |
The tidal volume, vital capacity, inspiratory capacity and expiratory reserve volume can be measured directly with a
Determination of the residual volume is more difficult as it is impossible to "completely" breathe out. Therefore, measurement of the residual volume has to be done via indirect methods such as radiographic planimetry,
In absence of such, estimates of residual volume have been prepared as a proportion of body mass for infants (18.1 ml/kg),[12] or as a proportion of vital capacity (0.24 for men and 0.28 for women)[13] or in relation to height and age ((0.0275* Age [Years]+0.0189*Height [cm]−2.6139) litres for normal-mass individuals and (0.0277*Age [Years]+0.0138*Height [cm]−2.3967) litres for overweight individuals).[14] Standard errors in prediction equations for residual volume have been measured at 579 ml for men and 355 ml for women, while the use of 0.24*FVC gave a standard error of 318 ml.[15]
Online calculators are available that can compute predicted lung volumes, and other spirometric parameters based on a patient's age, height, weight, and ethnic origin for many reference sources.
British rower and three-time Olympic gold medalist Pete Reed is reported to hold the largest recorded lung capacity of 11.68 litres;[16][17][18] US swimmer Michael Phelps is also said to have a lung capacity of around 12 litres.[17][19]
Weight of breath
The mass of one breath is approximately a gram (0.5-5 g). A litre of air weighs about 1.2 g (1.2 kg/m3).[20] A half litre ordinary tidal breath[11] weighs 0.6 g; a maximal 4.8 litre breath (average vital capacity for males)[11] weighs approximately 5.8 g.
Restrictive and obstructive
The results (in particular
Type | Examples | Description | FEV1/FVC |
restrictive diseases | pulmonary fibrosis, Infant Respiratory Distress Syndrome, weak respiratory muscles, pneumothorax | volumes are decreased | often in a normal range (0.8–1.0) |
obstructive diseases | asthma, COPD, emphysema | volumes are essentially normal but flow rates are impeded | often low (asthma can reduce the ratio to 0.6, emphysema can reduce the ratio to 0.78–0.45) |
See also
References
- ^ "Lung Volumes". Physiopedia. Retrieved 2023-04-14.
- ISBN 978-1-4120-3089-2.
- ISBN 978-1-4354-1914-8.
- PMID 16963682.
- ISSN 0190-8286. Retrieved 2023-04-26.
- S2CID 852646.
- ^ "Study Findings – USC Children's Health Study".
- PMID 28615020.
- ^ ISBN 978-0-7817-6759-0.
- ISBN 978-81-8147-920-4.
- ^ OCLC 1020568457.)
{{cite book}}
: CS1 maint: location missing publisher (link - PMID 19897058.
- .
- PMID 9502364.
- PMID 3784877.
- ^ English Institute of Sport, 17 November 2006, test ID 27781
- ^ a b "Making sense of breathing, VO2max and lung capacity". worldrowing.com. Retrieved 2019-11-28.
- ^ "Pete Reed: Three-time Olympic rowing champion on spinal stroke, paralysis and the future". 2019-11-28. Retrieved 2019-11-28.
- ISSN 0307-1235. Retrieved 2019-11-28.
- ^ Atmosphere of Earth#Density and mass