Your lungs work hard. Even when you're resting, they're diligently transporting oxygen into your bloodstream and moving carbon dioxide out. They're part of a serious business run by an intricate structure of organs and tissues—aka your respiratory system. To keep you alive and breathing, your lungs are on the clock 24/7, 365 days a year. Breathing 12 to 15 times a minute, translating to 17,000 breaths a day or more than 6 million breaths a year. And no vacation days! Here's how they get the job done:

1,500 Miles of Airways

Your lungs are one of the largest organs in your body. The surface area of both lungs is roughly the same size as a tennis court and the total length of the airways running through them is 1,500 miles. That's about the distance from Chicago to Las Vegas.

When you breathe in—either through your nose or mouth—air moves from the throat down to the windpipe and into two main bronchial tubes that lead to each lung. These tubes then branch out into smaller passages called bronchioles, which deliver the air to small air sacs called alveoli. It's here where fresh oxygen from the air is exchanged for carbon dioxide in the blood.


Power of 2

You have two lungs, the left lung and the right lung. The left lung is slightly smaller and has a notch to give room for the heart. Each lung is divided into lobes—the left lung has two and the right lung has three—which are similar to balloons filled with sponge-like tissue. Each lobe receives air from its own branch of the bronchial tree, but they all have the same function: bringing oxygen into the bloodstream and removing carbon dioxide. That's why it's possible (but by no means ideal) to live with just one lung.


6 Liters of Capacity

When you inhale, your lungs expand to hold the incoming air. How much air they hold is called lung capacity and varies with a person's size, age, gender and respiratory health. The maximum amount of air an average adult male's lungs can hold is about six liters (that's the same as about three large soda bottles). There's some math involved to get to that number, but basically, it's adding up air from a normal breath, extra air you can force in, additional air you can force out after regular exhaling and the air that's left in the lungs after all that.


2,000 Gallons a Day

Every day, you breathe in just over 2,000 gallons of air—enough to almost fill up a normal-sized swimming pool. That's a lot of air. It's the amount needed to oxygenate approximately 2,000 gallons of blood pumped through your heart daily.

Because lungs are constantly exposed to the external environment, they need some protection from dust, germs and other unwanted matter. That's where mucus comes in. Your bronchial tubes are lined with cilia (they're like thin little hairs) that carry mucus up into your throat to trap those yucky intruders until you cough, sneeze, clear your throat or swallow to get rid of them.

80 Percent of the Work


The diaphragm is the chief muscle of breathing. This dome-shaped wall of muscle does the most of the breathing work by expanding and contracting the chest to draw air in and out of your lungs. If your lungs are healthy, that's about 80 percent. When lungs need to be more efficient (e.g., you have a lung disease that impairs breathing or even if you're an athlete or musician looking to boost performance) a common place to start is with breathing exercises, which are focused on the diaphragm.

Learn more about how to keep your lungs healthy.

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