Simplified Lung Volume and Capacity: Graph and Chart (2023)

Lung volume and capacity are important metrics to distinguish a normal lung from a diseased lung. But we are often confused between lung volume and lung capacity. If you are one of those who confuse all volumes and capacities, this article will help you to clarify the concept. In this article we will discuss:

• The normal range of volume and skills.
• Lung volumes and capacities in obstructive pulmonary disease.
• Lung volumes and capacities in restrictive lung disease.
• Because the lung volume is actually a part of the lung capacity.

By the end of this article, you'll be a little better off than you were before.

lung volume and capacity

Lung volume and capacity are measures of the amount of air in the lungs during normal and vigorous breathing. During breathing, air moves in and out of the lung system. Normal breathing has the least inflow and outflow of air, which increases as the respiratory rate increases while running, etc.

Thus, lung volume is a measure of the volume of gas/air entering and exiting during itnormalbreathing and forced breathing. The amount of air in the lungs can be divided into four (4) volumes and four (4) capacities.

Explanation of lung volume

Lung volume is the volume of gas that moves in and out during our inhalation and exhalation. It is measured in liters. So let's discuss how inspiration and flow are measured in different ways.

Four lung volumes are:

1. tidal volume.
2. Inspiratory reserve volume.
3. expiratory reserve volume.
4. Residual volumes.

#1 Current volume (TV): To understand tidal volume, sit relaxed in a chair and close your eyes. Now try to feel your inhalation and exhalation (expelled air) with your eyes closed. The volume of air that is inhaled or exhaled during this resting breath is the tidal volume. Therefore, tidal volume is defined as "The volume of gas inspired or exhaled during resting breathing is called the tidal volume".

#2 Inspiratorisches Reservevolumen (IRV): The inspiratory reserve volume is the maximum volume of air that can be inspired during a forced inspiration. In fact, it is the extra air to the tidal volume that can be inspired during forced inspiration.

To understand this, sit back relaxed in a chair and close your eyes. Now breathe deeply in and out to your maximum capacity. This extra air you breathe in addition to the tidal volume mentioned above is the RTI.

#3 Expiratory Reserve Volume (ERV): The expiratory reserve volume is defined as the amount of air that can be expelled during forced expiration. Now close your eyes and, after inhaling normally, try to exhale as much air as possible. This extra amount of air over and above the normal exhalation is the ERV.

#4 Restvolumen (RV): Even after a forced exhalation, some air remains in the lungs. This means that the lungs do not empty completely even after forced expiration. The amount of air that remains in the lungs after maximum expiration is the residual volume.

Therefore, it can be defined as the volume of air remaining in the lungs after the AER has been performed.

Explanation of lung capacities

The four lung capacities are:

1. inspiratory capacity.
2. vital capacity.
3. Functional remaining capacity.
4. Total Lung Capacity.

#1 Inspiratory Capacity (IC): Inspiratory capacity is the volume of air that can be inspired at the end of tidal expiration, or the volume of air that can be forcefully inspired after normal inspiration.

Therefore, it is the sum of Tidal Volume (TV) + Inspiratory Reserve Volume (IRV).

#2 Vital Capacity (VC): Vital capacity (VC) is defined as a change in lung volume after maximal inspiration followed by maximal expiration and is referred to as the vital capacity of the lungs. It is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume. The vital capacity of normal adults is between 3 and 5 liters.

It is the total volume of air in the lungs that is controlled at will. It is the sum of IRV + TV + ERV.

CV is actually Forced Vital Capacity. To measure it, first draw in maximum inspiration, then push all of the air into a gauge as quickly as possible.

#3 Functional Residual Capacity (FRC): It is the volume of air that remains after the current has expired. So it is the combination of RV + ERV.

#4 Total Lung Capacity (TLC): It is the total volume of air remaining in the lungs/thorax after maximal inspiration.

It is the sum of IRV + TV + ERV.

Lung Volume and Capacity Chart

We can plot all four of these lung volumes and four capacities on one chart. Again, carefully read the volume and capacity descriptions, and then try to interpret them using this table.

Table of normal lung volumes and capacities

The difference between obstructive and restrictive pulmonary disease

obstructive and restrictivelung diseaseshows different lung volumes and capacities. All lung capacities are reduced in restrictive pulmonary disease and all increased in obstructive pulmonary disease. Let's try to understand it through this diagram.

Factors affecting lung volume and capacity

There are many factors that affect static lung volumes/capacities. Factors such as age, gender, weight, height and ethnicity are the most important physiological determinants of static lung volumes/capacities. However, there are other factors that need to be considered. Like, physical activity, regular exercise, especially swimming and resistance training. Alternatively, ascent to high altitudes can decrease lung volume, likely due to increased pulmonary blood flow, pulmonary edema, or premature closure of the small airways (1).

Let's try to figure out how age affects the volume and capacity of the lungs.

Effect of age on lung volumes/capacities

The respiratory system undergoes several anatomical, physiological, and immunological changes with age. Structural changes include chest wall and thoracic spine deformities that compromise overall respiratory system compliance and increase the work of breathing. The strength of the respiratory muscles decreases with age and can impair an effective cough, which is important for clearing the airways (2). All of these factors affect lung volumes and capacities, so we recommendbreathing exercisesimportant for respiratory health. When excess sputum accumulates in the lungs, it also affects breathing, we can get rid of it naturally by following the instructionsPosturale Drainagepositiontechnology at home

The lungs mature between the ages of 20 and 25, and later aging is associated with a progressive decline in lung function. Alveolar dead space increases with age, affecting arterial oxygen without affecting carbon dioxide excretion. Receptors in the airways undergo functional changes with age and are less likely to respond to drugs used in their younger counterparts to treat the same conditions. Older adults have a reduced sense of breathlessness and a reduced respiratory response to hypoxia and hypercapnia, making them more susceptible to respiratory failure during conditions of high demand (i.e., heart failure, pneumonia, etc.) and possible sequelae (2).

last word

There are a number of factors for thisinfluenceLung volumes and capacities. All of these volumes are measured using techniques that we will talk about later.

Another read: What is the bucket handle movement of the ribs, its anatomy?

Reference:

1. Lutfi, M. F. The physiological basis and clinical importance of lung volume measurements.Multidisciplinary Respira Med12,3 (2017).https://doi.org/10.1186/s40248-017-0084-5
2. Sharma, G & Goodwin, J (2006). Influence of aging on the physiology and immunology of the respiratory system.Clinical interventions in old age,1(3), 253–260.https://doi.org/10.2147/ciia.2006.1.3.253