The lungs have two main functions. One is to get oxygen from the air into the body. The other is to remove carbon dioxide from the body. Oxygen is needed by the body to work properly. Carbon dioxide is a waste gas the body produces when it uses oxygen.
During breathing, air enters and exits the lungs. When you breathe in (inhale), air flows through the airways into the lungs. The airways are made of stretchy tissue. Bands of muscle and other support tissue wrap each airway to help keep them open.
Air keeps flowing into the lungs until it fills tiny air sacs called alveoli. Blood circulates around these air sacs through tiny blood vessels. Oxygen crosses into the bloodstream at the place where the blood vessels and air sacs meet. This is also where carbon dioxide crosses from the bloodstream into the lungs to be breathed out (exhaled).
Changes in bones and muscles of the chest and spine:
Bones become thinner and change shape. This can change the shape of your ribcage. As a result, your ribcage is less able to expand and contract during breathing.
The muscle that supports your breathing, the diaphragm, becomes weakened and may prevent you from inhaling and exhaling enough air.
These changes in your bones and muscles result in a lower oxygen level in the blood that supplies your body. Also, less carbon dioxide is removed from your body. Symptoms such as tiredness and shortness of breath can result.
Changes in lung tissue:
Muscles and other tissues that are near your airways lose their ability to keep the airways completely open. This causes the airways to close easily.
Aging also causes the alveoli to lose their shape and become baggy.
These changes in lung tissue can allow air to get trapped in your lungs. Not enough oxygen enters the capillaries and less carbon dioxide is removed. This makes breathing hard.
Changes in the nervous system:
In older persons the part of the brain that controls breathing may lose some of its function. Your lungs are not able to get enough oxygen. And not enough carbon dioxide leaves the lungs. Breathing gets more difficult.
Nerves in your airways that trigger coughing are not as sensitive as before to particles such as smoke or germs. Large amounts of particles can collect in the lungs and are hard to cough up.
Changes in the immune system:
As you age, your immune system can get weaker. This means your body is less able to fight lung infections and other diseases.
Your lungs are also less able to recover after exposure to smoke or other harmful particles.
As a result of these changes, older persons are at increased risk of:
Low oxygen level, which reduces the body's ability to fight diseases
Abnormal breathing patterns, resulting in problems such as sleep apnea (episodes of stopped breathing during sleep)
To decrease the effects of aging on the lungs:
Do not smoke. Smoking harms the lungs and speeds up aging of the lungs.
Do physical exercise to improve lung function.
Be up and about. Lying in bed or sitting for long periods allows mucus to collect in the lungs. This puts you at risk of lung infections. This is especially true right after surgery or when you are ill.
As You Grow Older, You Will Have Other Changes, Including:
Sharma G, Goodwin J. Effect of aging on respiratory system physiology and immunology. Clin Interv Aging. 2006;1(3):253-260.
Janssens J-P. Aging of the respiratory system: impact on pulmonary function tests and adaptation to exertion. Clin Chest Med. 2006;26:469-484.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.