By The Breath Source
How Does Breathing Affect Running Endurance?
Breathing affects running endurance by determining how efficiently oxygen is delivered to the muscles and how effectively carbon dioxide and metabolic waste are removed from the body.
Many runners focus entirely on their legs and cardiovascular fitness, neglecting the primary engine of endurance: the respiratory system. Inefficient breathing, such as shallow chest breathing or chronic mouth breathing, forces the heart to work harder and accelerates the onset of fatigue. When you optimize your breathing mechanics, you improve your physiological economy. This means you can maintain the same pace with a lower heart rate and reduced perceived exertion, allowing you to run longer and recover faster.
Why is Nasal Breathing Better for Running?
Nasal breathing is better for running because it increases nitric oxide production, warms and humidifies the air, and improves oxygen extraction by utilizing the Bohr Effect.
Research shows that nasal breathing during aerobic exercise can be up to 22% more efficient than mouth breathing. The nose acts as a turbine, pressurizing the air and driving it deeper into the lower lobes of the lungs, where blood flow is greatest. Additionally, nasal breathing harnesses nitric oxide, a vasodilator that opens blood vessels and improves oxygen delivery to working muscles. While it may feel restrictive initially, adapting to nasal-only breathing at lower intensities trains the body to tolerate higher levels of carbon dioxide, which ultimately improves oxygen release at the cellular level.
What is Rhythmic Breathing for Running?
Rhythmic breathing is the practice of synchronizing your inhale and exhale with your footfalls to distribute impact stress evenly across both sides of your body.
When you exhale, your diaphragm relaxes, reducing core stability. If your exhale always lands on the same foot, that side of your body absorbs more impact force, increasing the risk of injury. A common rhythmic breathing pattern is a 3:2 ratio, inhaling for three steps and exhaling for two. This odd-numbered pattern ensures that the exhale alternates between the left and right foot strikes, balancing the mechanical load and improving overall running efficiency.
What Do Breath Masters Say About Athletic Breathing?
Breath Masters teach that athletic breathing is about adaptability and efficiency, using the breath to control the nervous system's response to physical stress.
AJ Fisher brings an exercise science perspective, using her HYPOXiX and Breathography methods to synchronize controlled breathing directly with movement mechanics. She emphasizes that the diaphragm is not just a respiratory organ, but a primary core stabilizer, and optimizing its function is critical for maintaining form and preventing injury during a run. AJ teaches that most athletes over-breathe during exercise, not because they need more oxygen, but because they lack the deep core strength to manage intra-abdominal pressure. "When you strengthen your diaphragm to be able to take a complete inhalation," she notes, "the diaphragm pushes down like a parachute toward those tight areas," providing essential stability and lymphatic drainage for high-impact activities like running.
Josh Seiler focuses on the critical balance between exertion and autonomic regulation. He teaches that nasal breathing isn't about getting less oxygen, but about using oxygen more efficiently to build endurance and accelerate recovery. In his work with athletes, Josh emphasizes that relying solely on mouth breathing during training keeps the body locked in a chronic sympathetic (fight-or-flight) state, which delays healing and increases oxidative stress. "Control your breath, control your performance," he advises, recommending structured practices like box breathing to help runners stay centered, lower their perceived exertion, and shift smoothly into a parasympathetic recovery state the moment the run ends.
Jesse Coomer highlights the importance of carbon dioxide (CO2) tolerance for endurance athletes. He notes that the feeling of "breathlessness" or panic during a hard run is rarely a lack of oxygen, but rather a low physiological tolerance for rising CO2 levels in the blood. When runners breathe fast and shallow, they offload too much CO2, which paradoxically disrupts oxygen delivery to the muscles. "Through breath training, you can improve CO2 tolerance, optimize oxygen delivery, and build a more resilient nervous system," Jesse explains. He trains athletes to use slow, nasal breathing and extended breath holds to delay fatigue and stay sharper for longer under physical pressure.
Ed Harrold is a pioneer in bringing yoga breathing (pranayama) into the Western sports paradigm. He teaches that proper athletic breathing begins at the nose, advocating for nasal dominance to maximize respiratory muscle training. Ed explains that nasal diaphragmatic breathing directly signals the parasympathetic nervous system, even during physical exertion. This allows runners to shift out of a pure stress response, conserving energy and transforming fat into fuel more efficiently. In his work with athletes, he notes that extending the exhale acts as a mechanical signal to slow the heart rate and maintain composure during endurance events. "Breaths per minute is going to dictate your heart rate," Ed explains, "and the lower the heart rate, the more sustainable power you are going to have to achieve your goals."
What Should You Begin Noticing?
You should begin noticing the relationship between your breathing pace and your heart rate, observing how a slower, controlled exhale can physically lower your exertion level.
Technology may support awareness, but breath develops awareness. During your next run, notice your default breathing pattern. Are your shoulders rising toward your ears? Are you breathing exclusively through your mouth? Try shifting to nasal breathing for just five minutes. Notice the initial urge to gasp for air, and observe how your body adapts as you maintain the rhythm. The goal is not to force a specific pattern for the entire run, but to build interoceptive awareness of how your breath dictates your physical state.
Guided Practices for Runners
To turn understanding into experience, explore these specific sessions inside The Breath Source app:
Frequently Asked Questions
Should I breathe through my nose during a sprint?
Nasal breathing is highly effective across all running intensities, including sprinting. When CO2 builds rapidly during a maximal effort, mouth breathing is not the only option and is not necessarily the most efficient one. A nasal technique called Performance Breathing, or Kapalabhati, uses rapid, forceful nasal exhales to burn off excess CO2 quickly and reset the respiratory system without abandoning nasal dominance. Even 2 or 3 rapid nasal inhales followed by a strong nasal exhale can clear the CO2 spike and allow the runner to return to a controlled nasal rhythm. This approach keeps the body in a more efficient oxygen-delivery state than switching to mouth breathing, which bypasses nitric oxide production and can accelerate overbreathing.
How do I stop getting side stitches when I run?
Side stitches are often caused by shallow chest breathing and a lack of core stability. Transitioning to deep, diaphragmatic breathing and employing a rhythmic breathing pattern (like the 3:2 ratio) can reduce the mechanical stress on the diaphragm and alleviate side stitches.
Can breathwork improve my VO2 max?
Yes. Specific breathwork protocols, particularly those involving breath holds and restricted nasal breathing, can simulate high-altitude training. This stimulates the production of red blood cells and improves the body's overall oxygen-carrying capacity, effectively increasing VO2 max over time.
Related Resources
- Download The Breath Source App & Start Your Free Trial
- Join Live Classes and BreathXChange Events
- Explore the Breath Education Section In Exercise Performance
- Build Your Own My Flow Practices Inside The App
References
- McConnell, A. K. (2013). Respiratory Muscle Training in Sports. Sports Medicine.
- Recinto, C., et al. (2017). Effects of Nasal or Oral Breathing on Anaerobic Power Output and Physiological Responses. International Journal of Kinesiology and Sports Science.
- Bryan, N. S. (2025). #124 Dr. Nathan Bryan: Nitric Oxide Expert. Take A Deep Breath Podcast, Spotify.
- Coomer, J. (2025). The Science of CO2 Tolerance: Why It Matters for Your Health and Performance. Jesse Coomer.
- Harbour, E., et al. (2022). Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running. Frontiers in Physiology.
- Summit Daily. (2017). Proper breathing begins at the nose, according to author Ed Harrold. Summit Daily.
- Dallam, G., et al. (2018). Effect of Nasal Versus Oral Breathing on Vo2max and Physiological Economy in Recreational Runners. Journal of Sports Research.
- Brindisi, G., Fisher, A. J., et al. (2024). Intermittent Hypoxic Breathing with Exercise Mimics Hypoxic Training SpO2 and Improves Waist Circumference and RMR in Obese Women. International Journal of Exercise Science: Conference Proceedings.
- Fisher, A. J. (2025). Breathwork During Exercise: A Simple 5-Minute Routine. HYPOXiX Blog.
