What Is Expiratory Residual Volume (ERV)?
Expiratory reserve volume (ERV) is the amount of air that remains in your lungs after you exhale all the air from your lungs. This is a measure of how much oxygen is left in your blood following inhalation and exhalation. You may have heard it referred to as inspiration reserve volume or inspiration factor.
The term “reservoir” refers to the space between your lungs and your heart. When you inhale, some of the air leaves your lungs through this reservoir while some of it enters your chest cavity through other spaces such as bronchi and veins.
Respiration is a series of muscular contractions that are controlled by nerves located in various parts of the brain stem, spinal cord, respiratory muscles, diaphragm and abdominal organs. These contractions cause the air to move from one location in your body to another.
Inhaled air moves into the alveoli (air sacs) in your lungs where it is stored until it reaches the capillaries of your lungs. There, oxygenated blood returns to the heart via arteries and veins.
Oxygen-rich blood then flows back out of the lungs through pulmonary veins and bronchial tubes.
Other parts of inhaled air go to the respiratory membrane and into the chest wall where they are stored for use. The space between your lungs and your heart is called the reservoir.
How Is It Measured?
The volume of air that remains in your lungs after you exhale is measured in liters and is referred to as your expiratory reserve volume (ERV).
In essence, your ERV can be roughly calculated by taking the difference between the amount of air that you exhale and the amount of air that you forcibly exhaled.
What Is The Normal Volume Of ERV?
The average normal volume of ERV is 200 milliliters for men and 175 milliliters for women.
How Is It Different From Expiratory Volume?
The expiratory volume is a measure of the total amount of air that you exhale from your lungs. It is a sum of the air that remains in your lungs after exhalation and your expiratory reserve volume (ERV).
The total volume of air that you exhale is measured in liters and is referred to as your expiratory volume.
In essence, the expiratory volume is a measure of the total amount of air that you exhale from your lungs. It is measured in liters and refers to the sum of the air that remains in your lungs after exhalation and your ERV.
What Is The Normal Volume Of Expiratory Volume?
The normal volume of expiratory volume is 500 milliliters.
Can It Be Measured In Different Units?
Your expiratory volume can be measured in different units. In the medical field, and particularly in the United States, it is most commonly measured in cubic centimeters. Other air quantities such as liters may be used to measure the total amount of air that you exhale.
Sources & references used in this article:
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Fluid volume redistribution and thoracic volume changes during recumbency by SM Tenney – Journal of Applied Physiology, 1959 – journals.physiology.org
Improvement of dyspnea after bariatric surgery is associated with increased Expiratory Reserve Volume: a prospective follow-up study of 45 patients by L Boissière, JM Perotin-Collard, E Bertin, I Gaubil… – PLoS …, 2017 – journals.plos.org
Lung volumes of singers by SS Heller, WR Hicks, WS Root – Journal of Applied …, 1960 – journals.physiology.org
Lung volumes: measurement, clinical use, and coding by JD Flesch, CJ Dine – Chest, 2012 – Elsevier
