Age is a factor in diminished lung capacity
Q: I recently started going to a yoga class at our community center. We were doing deep breathing, and it felt like my lungs weren't filling up as much as they used to. Do your lungs get less elastic when you get older? Can that be reversed?
A: The lungs, which are a pair of balloonlike organs located in the chest cavity, are really quite remarkable. With each inhale, they make possible the rapid transfer of life-sustaining oxygen to the bloodstream. Each exhale off-loads carbon dioxide, which is a waste product.
The lungs are firm enough to maintain their shape, yet elastic enough to expand and contract with each of the estimated 22,000 (!) breaths we take each day. They are also a marvel of bioengineering. A network of branching airways gradually decrease in size, terminating in clusters of minute sacs known as alveoli. In a healthy adult, these number between 300 million to 500 million and provide between 540 and 810 square feet of surface area for the gas exchange we discussed earlier.
The elasticity of our lungs arises from two distinctive features. One is a protein known as elastin. When tissues in the body require elastic recoil to fulfill their function, elastin is usually present. Collagen, a structural and pliant protein, also plays an important role.
Another factor in lung elasticity is surface tension. This is specific to the tiny sacs of the alveoli. Small and fragile, they rely on a substance known as a surfactant to provide the surface tension needed to keep them from collapsing when we exhale. The combined actions of elastin, collagen and surface tension, along with a supporting network of muscles and connective tissues, create lung capacity. This is the total volume of air in the lungs when you breathe inasmuch as possible.
When it comes to a decrease in lung capacity, a number of factors come into play. A universal one is age. While lung development concludes at about age 8, our lungs increase in size and capacity as we continue to grow. Lungs reach maturity by about age 20 or 25. About a decade later, lung capacity begins a gradual age-related decline. Exercise, general health and smoking each play a role in how much and how quickly this occurs.
Additional causes of decreased lung capacity include respiratory illnesses, such as chronic bronchitis, emphysema, asthma and COPD. Severe pneumonia, which causes inflammation, can scar the delicate tissues of the alveoli and also lead to diminished lung capacity.
Unfortunately, changes to the tissues that contribute to lung elasticity cannot be reversed. However, you can take steps to help maintain — and perhaps improve — lung capacity. The yogic deep breathing you have begun doing is excellent for that. So is exercise in general. The trick is to make both a part of your daily routine. A healthful diet and maintaining a healthy weight are also important.
And we hope this goes without saying, but smoking is the enemy of lung health, and health in general. Please, if you are a smoker, consider crafting a strategy to quit.
• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.
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