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Lung capacity is the volume of air that goes into and out of our lungs.
It varies with age, size, and fitness. For example, cyclists and runners have a lot of lung capacity, and smokers have less. On average, lungs can hold about 13 pints, which is about ten times the amount of air in a normal breath. But how much air is in a normal breath? The answer depends on what you are doing and where you live. In any case, lungs rarely work to full capacity—we typically use only about one-third of our capacity. Here’s how it breaks down.