Aging changes in the lungs

Information

The lungs have two primary finctions: acquire oxygen from the air, which is required for life, and to remove carbon dioxide from the body, which is a byproduct of many of the chemical reactions that sustain life.

During breathing, air enters and exits the lungs. It flows in through increasingly small airways, finally filling tiny sacs called alveoli. Blood circulates around the alveoli through capillaries. Where the capillaries and alveoli meet, oxygen crosses into the bloodstream. At the same time, carbon dioxide crosses from the bloodstream into the alveoli to be exhaled.

The lungs are continuously being exposed to particles in the air, including smoke, pollen, dust, and microorganisms. Therefore, another a major function of the lungs is to protect from any diseases that may caused by inhaled particles.

AGING CHANGES

An average person continues to slowly make new alveoli until about age 20. After this age, the lungs begin to lose some of their tissue. The number of alveoli decreases, and there is a corresponding decrease in lung capillaries. The lungs also become less elastic due to various factors including the loss of a tissue protein called elastin.

Changes in the bones and muscles result in a slightly increased front-to-back chest diameter. Loss of bone mass in the ribs and vertebrae, and mineral deposits in the rib cartilage, change the spine curvature. There may be side-to-side curvature (kyphosis) or increased front-to-back curvature (scoliosis) or lordosis.

The maximal force one can generate on inspiration or expiration decreases with age, as the diaphragm and muscles between the ribs (intercostals) become weaker. The chest is less able to stretch to breathe, and the pattern of breathing may change slightly to compensate for decreased ability to expand the chest.

EFFECT OF CHANGES

Maximum lung function decreases with age. The amount of oxygen diffusing from the air sacs into the blood decreases, the rate of air flow through the airways slowly declines after age 30, and the maximal force one is able to achieve on inspiration and expiration decreases. Usual breathing should remain adequate, and even a very old person should, under most circumstances, be able to breathe without effort.

However, when there is a need for increased breathing, the lungs may not be able to keep up with the demand. As aging continues, there may be a decreased capacity for exercise, and high altitude may cause problems.

An important change for many older people is that the airways close more readily. The airways tend to collapse when an older person breathes shallowly or when in bed for a prolonged time. Breathing shallowly because of pain, illness, or surgery causes an increased risk for pneumonia or other lung problems. As a result, it is important for older people to be out of bed as much as possible, even when ill or after surgery.