Why Do Runners Breathe Heavily After A Sprint Race? CO2 As Your Worst Enemy After Sprint

Why Do Runners Breathe Heavily After A Sprint Race

Have you wondered, “why do runners breathe heavily after a sprint race?” Runners breathe heavily after a race due to a build-up of carbon dioxide in their bodies.  

When I first started running, I used to get so out of breath. Which got me wondering, why do runners breathe heavily after a sprint race? It turns out it's to do with a build-up of carbon dioxide in the body.

Runners find themselves breathing heavily to expel carbon dioxide and take in more oxygen. 

Why Was I Out of Breath?

In order to understand the answer to the question, we first have to start by reviewing how the respiratory system works. You take in air through the mouth and nose, which then travels to the lungs. 

Once this air reaches the lungs, the oxygen is exchanged for carbon dioxide in the blood. This carbon dioxide is exhaled as a gas.

Carbon dioxide is created as a by-product of cell metabolism. The metabolism process is more than just burning fat to create energy. It's a complex process that breaks down several different types of chemicals in the body and creates several different types of by-products. 

Why Do Runners Breathe Heavily After A Sprint Race
Carbon dioxide must be expelled as it is a waste product during breathing

Some of these products can be used to create energy in the cell, but others are simply waste products. Carbon dioxide is an example of a waste product; it does not have any useful function in the body, so it must be expelled.

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Carbon Dioxide Build-Up

When runners feel pain in their lungs when they run, it's because there is a build-up of carbon dioxide in their blood. The pain that anyone feels when their body is deprived of air isn't because of the lack of oxygen but because of the build-up of carbon dioxide.

As a person runs, their body metabolizes substances such as glucose and fat and turns them into by-products such as carbon dioxide. By breathing, this carbon dioxide can be released.

The problem for many runners is that while they think they are breathing normally or even heavier while they are running, odds are they are taking shallower breaths. When you're active, your body uses more oxygen to compensate, which means more carbon dioxide is left over. This extra carbon dioxide is then harder for the body to release due to the shallow breaths the runner is taking.

Chinese man and woman are out of breath after jogging in city park
Extra CO2 is harder for the body to release during running

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FAQs on Why Do Runners Breathe Heavily After A Sprint Race


Can Runners Do Anything To Feel Less Out Of Breath?

Learning to take deeper breaths while running can help, as it allows the carbon dioxide to leave the body in greater quantities.  

Does Being Out Of Breath Mean My Body Is Burning Fat? 

While being out of breath shows that the cells of your body are going through the process of metabolization, it is difficult to determine what substances those cells are metabolizing based solely on this one symptom.