How to Improve Shortness of Breath During Exercise

Breathing Tips and Exercises for Mountain and Endurance Athletes (and everyone else…)

If you’ve ever found yourself gasping for air halfway through a workout or struggling to catch your breath during a long run, you’re not alone. How to improve shortness of breath is a common challenge for mountain and endurance athletes (and anyone, really), but there’s more to it than just fitness levels or altitude. The secret lies in understanding and managing your carbon dioxide (CO₂) levels. This blog post will break down how CO₂ impacts your breath, how to measure your CO₂ tolerance, and—most importantly—how to improve it so you can feel less breathless and more in control during your next workout – and ultimately your next mountain adventure.

A man hunched over trying to catch his breath wearing a backpack on a mountain.
Photo by Tim Wenger and Matador Network

The Role of Carbon Dioxide in Shortness of Breath (Breathlessness)

Before diving into the “how-to,” let’s clarify what’s happening inside your body when you feel breathless. While it might seem counterintuitive, the sensation of breathlessness isn’t just about a lack of oxygen. Instead, it’s closely tied to the levels of carbon dioxide (CO₂) in your blood. CO₂ is a byproduct of metabolism, and your body needs a certain level of it to maintain the right pH balance.

In exercise physiology, it has been shown that rising CO₂ levels, even when oxygen is adequate, can trigger shortness of breath, highlighting the importance of CO₂ tolerance in endurance sports. Let’s take a closer look:

1. Chemoreceptors and CO2 Sensitivity:

  • Your body has chemoreceptors, primarily in the brainstem, that monitor the pH (and therefore levels of CO2) in your blood. These chemoreceptors are highly sensitive to changes in CO2 concentration.
  • When CO2 levels rise, these receptors send signals to your brain, triggering an increase in the rate and depth of your breathing. This is your body’s way of trying to expel the excess CO2 and restore balance.

2. Acidosis and Breathing Response:

  • Elevated CO2 leads to an increase in hydrogen ions (H+) in the blood, which makes the blood more acidic (a condition known as acidosis).
  • The brain interprets this acidity as a sign that the body isn’t getting enough oxygen, even if oxygen levels are normal, and it triggers a strong urge to breathe more deeply or rapidly. This results in the sensation of breathlessness.

3. Shortness of Breath During Exercise:

  • During intense exercise, your muscles produce more CO2 as a byproduct of increased energy metabolism. If your respiratory system can’t keep up with expelling this excess CO2, you’ll start to feel breathless.
  • Interestingly, it’s often the buildup of CO2, rather than a lack of oxygen, that drives the need to breathe harder during exercise.

4. CO2 and High Altitude:

  • At high altitudes, the lower atmospheric pressure reduces the amount of oxygen available, but your body still produces CO2 at the same rate.
  • The reduced oxygen availability causes your body to react – by breathing more rapidly, and potentially shallowly if your breathing mechanics aren’t optimal – leading to a faster-than-usual off-load of CO2, which can lead to respiratory alkalosis. This has many consequences, including your muscles not being able to receive oxygen from your hemoglobin (red blood cells) known as something called the Bohr Effect.

To conclude, it is important to work on your own carbon dioxide tolerance so that you can keep your breath through the nose, slow, and controlled – even in moments of higher exercise intensity. This will enable you to oxygenate your body more efficiently during workouts. 

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Measuring Your Personal CO₂ Tolerance

So, how do you know where you stand with your CO₂ tolerance? Enter the Bolt Score, a simple yet effective test from the Oxygen Advantage program, created by Patrick McKeown. The Bolt Score measures the time it takes for you to feel the first urge to breathe after a normal exhale, giving you a baseline for your CO₂ tolerance.

Here’s how to do it:

  1. Sit comfortably and breathe normally through your nose.
  2. Take a normal breath in and out, then pinch your nose to hold your breath.
  3. Start a timer and count the seconds until you feel the first clear urge to breathe.
  4. Release your nose and resume normal breathing.

The time in seconds is your Bolt Score. A low score indicates a low CO₂ tolerance, while a higher score shows better adaptation to elevated CO₂ levels. Don’t worry if your score is on the low side—there are plenty of exercises you can do to improve it.

End-Tidal CO2 Monitor (Capnography)

For a more precise measurement, an end-tidal CO2 monitor can be used. This device measures the concentration of CO2 in the air you exhale, particularly at the end of each breath. It’s commonly used in medical settings but can also be utilized by athletes and breathwork practitioners. If interested in this very precise type of measurement, consult your doctor or exercise physiologist.

How to Perform with a Capnography Device:

  1. Attach the sensor to your nose or mouth, depending on the device type.
  2. Breathe normally while the device records your CO2 levels during exhalation.
  3. Review the data provided by the monitor, which will show your CO2 levels in real-time.

Interpreting Your Results:

  • Low End-Tidal CO2: Might indicate over-breathing or hyperventilation, which can lead to low CO2 tolerance.
  • Normal End-Tidal CO2: Indicates balanced CO2 levels and typical tolerance.
  • High End-Tidal CO2: Could suggest good CO2 tolerance, but if excessively high, it might require medical evaluation.
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A man running on a trail in the mountains with a peak in the distance.

How to Stop Getting Out of Breath When Exercising: Exercises to Improve your CO2 tolerance

Improving your CO₂ tolerance can have a significant impact on how you feel during exercise, particularly in high-altitude environments or during intense endurance efforts. Below are some exercises, drawn from both the Oxygen Advantage program and Recal Travel’s High Altitude Breathwork Training, that can help you train your respiratory system to handle higher CO₂ levels more effectively.

1. Nasal Breathing During Exercise

One of the simplest yet most effective ways to stop getting out of breath while exercising and improve your CO2 tolerance is by focusing on nasal breathing during exercise. Breathing through your nose naturally increases CO₂ levels because it slows down your breath and forces your body to adapt. Dr. George Dallam’s research found that athletes who practiced nasal breathing experienced improved aerobic capacity and a reduced sense of effort during exercise, making it a valuable tool for endurance athletes. Whether you’re running, hiking, or cycling, commit to nasal breathing. If you start feeling breathless, slow down rather than switching to mouth breathing – this will help in the long run.

2. The ‘Breathe Light’ Exercise

This exercise, from the Oxygen Advantage program, helps you gradually build CO₂ tolerance:

  1. Breathe softly in and out through your nose, focusing on relaxing your diaphragm.
  2. Slow down your breathing to the point where it feels like you’re not getting quite enough air, creating a slight air hunger.
  3. Maintain this light breathing for 3-5 minutes, then return to normal breathing.

Patrick McKeown’s research on light breathing exercises demonstrates that these techniques can significantly boost CO₂ tolerance and enhance respiratory efficiency. The slight discomfort you feel is your body adapting to higher CO₂ levels, which will pay off during strenuous activities.

3. High Altitude Simulation (HAS)

Inspired by Recal’s high-altitude breathwork training, HAS simulates the conditions of high-altitude environments:

  1. Start with a few normal breaths to balance the pH of your blood.
  2. After an exhale, pinch your nose and hold your breath and walk for 10-15 paces (or longer as you progress).
  3. After the hold, exhale fully and pause for 2-3 seconds before inhaling again.
  4. Repeat for 5-10 cycles.

This exercise mimics the reduced oxygen levels at altitude, pushing your body to adapt and improving both oxygen and CO₂ tolerance. As you get more advanced, you can begin to jog or walk up/down stairs or a hill while holding your breath. For full training plan options, click here.

Note: this type of exercise should be done by healthy individuals only, with no severe heart conditions.

4. Extended Exhalation Breathing

This exercise emphasizes the exhale. Dr. Marc Kowalski’s studies found that exercises focused on extended exhalation significantly increased CO₂ tolerance and reduced breathlessness during high-intensity workouts.

  1. Inhale deeply through your nose.
  2. Exhale as slowly and fully as possible through your nose (maybe you can work to a 30, 45, 60, or even 75-second exhale), and try to empty your lungs completely.
  3. Pause at the end of the exhale for 2-3 seconds before taking your next breath.

Perform this exercise for 5-10 minutes daily to improve your CO₂ tolerance and overall respiratory efficiency.

5. Box Breathing

Box Breathing is about controlling the breath, making it an effective way to improve CO₂ tolerance:

  1. Inhale through your nose for 4 seconds.
  2. Hold your breath for 4 seconds.
  3. Exhale slowly through your nose for 4 seconds.
  4. Hold your breath again for 4 seconds before starting the next cycle.

Gradually increase the duration (instead of 4 seconds, work to 5, 6, or more) of each phase to further challenge your CO₂ tolerance.

Respiratory Muscle Training and Its Role in Shortness of Breath During Exercise

Beyond CO₂ tolerance, respiratory muscle training (RMT) plays a pivotal role in improving exercise tolerance—particularly for endurance athletes and mountaineers. By strengthening the muscles involved in breathing, such as the diaphragm and intercostals, RMT reduces the perceived effort of breathing during intense exercise. Studies, including those by Dr. Alison McConnell, a pioneer in respiratory muscle training, have shown that athletes who incorporate RMT into their routines experience less fatigue, lower heart rates, and improved stamina during prolonged physical activity. This training essentially conditions your respiratory system to handle the demands of high-altitude or endurance exercise, making every breath more efficient and less taxing. Whether you’re climbing steep mountain paths or pushing through the final miles of a marathon, stronger respiratory muscles mean you can go further, with less strain, and recover faster. Respiratory muscle training is also an important element of Recal’s High Altitude Breathwork Training program.

Conclusion: Breathe Easier, Perform Better

Feeling breathless during a grueling endurance workout or on the mountain doesn’t have to be your reality. By understanding the role of CO₂ in breathlessness and taking steps to improve your CO₂ tolerance through targeted exercises, you can enhance your performance and comfort during even the most challenging activities. And don’t sleep on Respiratory Muscle Training as well, a crucial ingredient in the formula for success on the mountain and in endurance training.

Start incorporating these exercises into your routine, and watch as your breathlessness decreases and your endurance soars. After all, the mountain may be steep, but your breath should never be the thing holding you back.

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~ Message from Recal ~

Thanks for stopping by our blog. Here at Recal, we offer breathwork-based coaching to help you prepare for life’s greatest endeavors. 

The latest program we offer is High Altitude Breathwork Training to get you ready for the mountain, even if you live at sea level. We also created Guidebook to use as a daily journaling tool; it has helped leaders around the world live more focused and fulfilling lives.

If you’re curious about our Guides, click the links below to submit your information and receive a free digital copy:

We also have a strategic partnership with Oxygen Advantage and use their products (like mouth tape for sleep and SportsMask for altitude training) to help our community become better leaders through breathwork training and proper breathing habits. You can view their online breath courses and products by clicking here.  

We stand by the things that we offer and promote – and proudly use them ourselves.

If you have any questions, we’re here to help: email us at hi@recaltravel.com.