How to Breathe When You Run

Your breath is a powerful thing. It has the power to calm the mind and boost energy. Not surprisingly, how you breathe when you run can have a huge impact on your running performance. Take too many or too few breaths and you feel breathless and short your body of the fuel it needs.

However, many of us don’t think much about how we breathe while running. It should come naturally right? Wrong. That’s why I connected with physical therapist and mother runner Melanie Connell. Melanie is the owner of Remedy Physical Therapy & Wellness in Southern California where she works with active females who have been sidelined by persistent pain and injury.

And, she’s blown my mind with breathing techniques that can make running feel easier: the secret has to do with Carbon Dioxide, not Oxygen. Crazy, right? Read on to how changing how you breathe can transform how you run.   

Melanie Connell
Melanie is a physical therapist and mother runner. She is the owner of Remedy Physical Therapy & Wellness in Southern California where she works with active females who have been sidelined by persistent pain and injury.

How to Breathe When You Run

Are you constantly out of breath when you increase your speed or distance? Do you have a hard time keeping your heart rate down during exercise?  Do you feel gassed after a workout? If you want to run faster and farther without the breathlessness and elevated heart rate, then keep reading. 

Related: 9 running hacks that make you run faster

It takes a lot of consistent training to be able to run farther and faster. Train too much too soon and you overload the body which may lead to injury. Scaling your performance must be a balance of recovery and training. One can’t focus solely on variables like speed, agility, strength, and power without also addressing sleep, food, hydration, and mindset.  There is one variable that’s often forgotten but has a valuable impact on both training and recovery. It’s called breathing.

The power of breath

Breathing is the secret sauce to energy efficiency. Everyone wants the ability to run faster and farther with less effort right? But how hard do you have to work to get there? It might not be as hard as you think. You can learn simple breathing techniques to regulate your breath during a run as well as downregulate your body during recovery. 

In order for your muscles to work efficiently during exercise, they need oxygen. The maximum amount of oxygen that your body transports and uses during exercise is called VO2 Max.

There’s a caveat though. It’s not as simple as breathing in more oxygen to help the muscles perform well. What typically doesn’t get explained in this process is the body’s necessary use of Carbon Dioxide (Co2).

Co2 is the gas needed to drive the oxygen from the red blood cells into the muscle. The amount of Oxygen you inhale isn’t the determining factor in how well your muscle uses that oxygen, Co2 is. One other important role of carbon dioxide is that it helps improve recovery and fatigue because it acts as an antioxidant and prevents muscle damage after exercise. The body’s tolerance to Co2 is what determines how fast you breathe. If you want to improve running performance (training + recovery) then learn how to breathe more efficiently and how to tolerate CO2. 

Here’s how.

how to breathe while running
There is a test you can take at home to guide your breathing.

Rhythmic breathing for runners

There are two categories athletes can fall into:

1) those who hold their breath, and 2) those who over-breathe.

Runners generally fall into the latter category. When you gasp for air during exercise you are offsetting carbon dioxide and typically have a harder time regulating your heart rate. Keeping your heart rate down is something runners typically seek to do as they improve performance.

The heart can’t be voluntarily controlled, but the breath can. So control your breath rate, control your heart rate.

One way to control your breath rate during a run is to keep it consistent. Inhale 3 steps. Exhale 3 steps. This type of rhythmic breathing slows the breathing rate and keeps it consistent to avoid huffing and puffing. The most efficient way to practice this is by inhaling and exhaling through the nose only. 

Related: How to keep running when you are tired

Why nasal breathing is good for runners

Nasal breathing prevents over-breathing and provides a better balance of Oxygen (O2) and Co2 exchange. Inhaling and exhaling through the nose creates better lung volume and oxygen saturation. This can give you better exercise intensity with less physical fatigue because the heart doesn’t have to work as hard or require as much oxygen for the workload. 

If you know you are a mouth breather then I would suggest practicing nasal breathing at rest first. So try it when sitting at your desk or walking around your house. Then attempt nasal breathing while on a 5 min leisurely walk with a low heart rate. Once that is tolerable, an attempt on a walk/jog while slowly increasing your need for oxygen as you try to control the breath. When you are ready to attempt nasal breathing out on a run, increase the run distance with nasal breathing before you attempt at faster speeds. 

Nasal breathing improves one’s tolerance to Co2 and leads to greater heart rate variability which is the ultimate marker of stress on the body. The ability to tolerate CO2 levels is an important performance factor. It’s also being studied and used as an important factor in panic and anxiety. Below is a test to determine your tolerance to carbon dioxide. 

Get more tips on how to breathe while running.

Co2 Tolerance Test for runners

Perform this test in a resting position.

    1.   2-3 second breaths through the nose only 

    1. Inhale 2-3 seconds
    2. Exhale 2-3 seconds 
    3. Repeat 3 times
  1. Time your exhale
    1. On the 4th breath cycle, take a big inhale through the nose
    2. Exhale long, slow, and continuous through the nose.  
    3. Time this exhale
  2. Range of time
    1. < 25 seconds
    2. 30-60 seconds *average
    3. >60 seconds

      box breathing for runners
      Box breathing can improve your breath by increasing your Co2 tolerance.
  3. The ideal range is to be able to exhale for at least 30 seconds. If you are less than 30 seconds then you can use box breathing as a way to improve your tolerance levels.
  4. Box breathing — each breath and hold are for the same amount of time. Attempt only in a rested position sitting or lying, not during activity. 
    1. Inhale 3-4 seconds
    2. Hold 3-4 seconds
    3. Exhale 3-4 seconds
    4. Hold 3-4 second
    5. Repeat 5 times
    6. If your timed exhale was greater than 30 seconds then start with 5 seconds each.

Better breathing while running starts with maintaining a better resting breath. In the same way that food, hydration, and sleep are daily habits that fuel performance, improving your breathing habits could be the key to your next PR. 

Thanks, Melanie! To learn more fun facts about breathing and the body, head to Melanie’s website at or follow her on Instagram at @remedyoc. 

PS-I’d love to help you reach your running goals whether it be to run your first 5k or run competitively! Email me at [email protected] with questions or check out my Coaching Services page!


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