You can only survive a few weeks without food and just a few days without water. But without air, you probably won’t last a few minutes.
The link between life and breath has always been clear, but it took modern science to reveal the mechanics at the cellular level. Food and water feed our cells, but they need oxygen to break it down. Cells also excrete another gas, carbon dioxide, as waste. The body’s circulation of these gases is called respiration. If respiration is compromised, cells get weak, sluggish, and may die prematurely.
Lungs are the organs best associated with respiration, but the process is crucial for all our cells. The better our cells can breathe, the healthier our whole body.
Our lungs drive respiration in two ways. First, they act like bellows, mechanically pumping air in and out of the body. Next, they transfer this air into and out of our blood with microscopic sacs called alveoli. With each breath, alveoli deposit oxygen into the blood and pull carbon dioxide out of it. We have hundreds of millions of alveoli facilitating this gas exchange. If one took all the alveoli from an adult pair of lungs and spread them out, it would equal about the size of a tennis court.
According to Dr. David Beuther, a pulmonologist at National Jewish Health, lung diseases typically target one of these two functions. Asthma, for example, is a bellows problem: airways become tight and inflamed, making it harder to inhale or exhale. Emphysema, a condition marked by scar tissue in the lungs, destroys alveoli.
“You actually get destruction of the air sacs, so your tennis court gets smaller and smaller in size,” Beuther said.
Chronic obstructive pulmonary disease, pneumonia, and other lung-related issues all impair our breathing in different ways. Various heart conditions can also leave us short of breath. But Beuther says you can have a perfectly healthy heart and lungs and still be gasping for air.
“Many times, it’s just because people are out of shape,” he said.
The lungs don’t work alone. Air exchange at the cellular level requires a full-body infrastructure: tiny blood vessels that can reach each cell. If the infrastructure deteriorates, so does cell function.
You may not notice the deterioration until you’re required to do something particularly strenuous. When you ask more from your muscles than they’re used to, they need more air circulation for the extra exertion. This is what causes all the huffing and puffing—your lungs are pumping harder to meet the demand of struggling cells.
Your lungs are working overtime, but respiration may not be able to reach the cells because there isn’t enough infrastructure to service them. “Imagine a neighborhood full of houses, but no streets. Trash builds up, and packages don’t get delivered,” Beuther said.
If you regularly engage in strenuous activity, both your body and breathing become more efficient. Exercise doesn’t just strengthen muscle tissue; it improves cellular respiration because working muscles develop a more intricate network of blood vessels.
“It’s easy to deliver things to the house, and the trash gets picked up regularly,” Beuther said. “You can train to do better at that.”
If we’re subjected to enough strenuous activity we begin to lose fat, and it’s the lungs that usher most of this fat out our body. Contrary to popular belief, fat doesn’t exit the body via the colon or miraculously turn to muscle. Instead, it breaks down into basic elements and we exhale it. In a 2014 study, researchers found that when a person burns off 22 pounds of fat, more than 18 of those pounds are expelled as carbon dioxide. The rest leaves as water.
Shedding excess fat also makes it easier to breathe. Beuther says fat can constrict the space that lungs need to fully expand, thus confining our bellows.
“Those with a big belly typically have low oxygen levels at night,” he said. “Gravity keeps the belly away from their lungs when they’re standing during the day, but when they lie down, it pushes up against the diaphragm and makes for shallow breathing.”