The vital capacity is the maximum amount of air that can be expelled from the lungs after a maximum inhalation effort. The average vital capacity for a woman is 3.0 liters, and for a man, it’s 4.2 liters. The vital capacity calculation is equal to the sum of the inspiratory reserve volume, tidal volume, and expiratory reserve volume.
What’s the vital capacity equation?
The vital capacity is the maximum amount of air that can be expelled from the lungs after a maximum inhalation effort. In healthy humans, this figure is around 6 liters.
As you may have guessed, it’s an important indicator of lung function; lower values can indicate disorders such as emphysema or asthma.
The vital capacity calculation is equal to the sum of the inspiratory reserve volume, tidal volume and expiratory reserve volume.
The equation for calculating vital capacity is VC = IRV + TV + ERV.
The total lung capacity (TLC) is simply VC minus RV, which is used as a reference point for other values such as residual volume (RV).
To understand the role of the diaphragm in breathing, it helps to understand a few things about the anatomy of your chest cavity. The thoracic cavity is divided into two sections: one that contains your organs (the pleural cavity) and one that doesn’t (the mediastinum). It’s this pleural cavity that houses your lungs, which are encased in membranes called visceral pleura.
The diaphragm is a muscle that separates these two parts of the thoracic cavity by attaching at its base to the sides of the lower vertebrae and running up through an opening at T12 where it connects with both lungs. When you inhale, what happens? Your diaphragm contracts—and expands! This expansion increases lung volume within its confines; as air rushes in from outside through tiny openings known as respiratory bronchioles on either side of each lung lobe, it compresses those tiny tubes before entering larger airways called bronchi (a plural form), which lead to alveoli where gas exchange occurs between oxygen-rich air and carbon dioxide-poor blood cells.
As the diaphragm relaxes, it returns to its resting position and lung volume is restored. Exhalation begins as air flows out of the lungs under pressure from residual air inlets, such as those between alveoli where oxygen is exchanged for carbon dioxide. This is known as passive exhalation. Active exhalation occurs when you consciously contract your abdominal muscles during expiration. This forces more air out of your lungs and creates an additional momentary vacuum that draws more fresh air into them through natural breathing reflexes that occur during inhalation.
The vital capacity (VC) is defined as the total volume of air that can be displaced from the lungs by maximal expiratory effort.
Among healthy adults, the average lung capacity is about 6 liters.
A spirometer is a diagnostic device that measures the amount of air you’re able to breathe in and out and the time it takes you to exhale completely after you take a deep breath.