Lung Capacity and Aging
Did you know that the maximum amount of air your lungs can hold—your total lung capacity—is about 6 liters? That is about three large soda bottles.
Your lungs mature by the time you are about 20-25 years old. After about the age of 35, their function declines as you age and as a result, breathing can slowly become more difficult over time.
There are several body changes that happen as you get older that may cause a decline in lung capacity:
Muscle and bone changes
- The diaphragm, the large muscle that moves air in and out of the lungs, gets weaker, decreasing the ability to inhale and exhale.
- Ribcage bones become thinner and change shape, altering the ribcage so that it is less able to expand and contract with breathing.
Lung tissue changes
- Muscles and tissues that usually keep airways open lose elasticity, causing some to close.
- Alveoli, the small sacs where the exchange of oxygen and carbon dioxide happens with the bloodstream, can lose their shape and become baggy.
Nervous system changes
- The part of the brain that controls breathing may no longer send as strong or clear a signal to the lungs.
- Nerves in airways that trigger coughing become less sensitive to foreign particles. When particles build up in the lungs, they can damage the lung tissue.
All of these changes can cause air to get trapped, decreasing the amount of oxygen moving in and carbon monoxide moving out of the bloodstream.
Measuring Lung Capacity
Spirometry is a diagnostic test that provides different measures of lung capacity. For the test, you blow into the mouthpiece of a device called a spirometer, which measures the amount and speed of air you can exhale.
Often used to diagnose chronic obstructive pulmonary disorder (COPD) or asthma, spirometry results are also used to see if your breathing has improved after treatment for a lung condition. Spirometry can be a useful indicator of lung age when your results are compared to others the average results of other people your age.
Some examples of spirometry measurements your healthcare provider will look at:
- Forced vital capacity: the maximum amount of air you can forcibly exhale from your lungs after fully inhaling. It is about 80 percent of total capacity, or 3.8 liters, because some air remains in your lungs after you exhale. Forced vital capacity can decrease by about 0.2 liters per decade, even for healthy people who have never smoked.
- Forced expiratory volume (FEV): the amount of air you can exhale with force in one breath. FEV1 is the amount of air you can exhale with force in 1 second. FEV1 declines 1 to 2 percent per year after about the age of 25, which may not sound like much but adds up over the course of a lifetime.
Keeping your lungs healthy is important as you age. See tips on how to take care of them.