Running: Optimal Breathing Strategies for Performance

Is it better to breathe through nose or mouth when running?

For most runners, a combination of nasal and oral breathing is optimal, with nasal breathing preferred for lower intensities to maximize physiological benefits, and oral breathing becoming necessary for higher intensities to meet increased oxygen demands.

The Physiology of Respiration During Exercise

Efficient respiration is paramount for running performance and overall health. When you run, your muscles demand more oxygen, and your body must efficiently remove carbon dioxide. The respiratory system, including the nose, mouth, pharynx, larynx, trachea, bronchi, and lungs, works tirelessly to facilitate this gas exchange. Understanding the unique roles of the nasal and oral passages in this process is key to optimizing your breathing strategy.

The Case for Nasal Breathing (Nose Breathing)

Breathing exclusively through your nose during exercise, particularly at lower intensities, offers several significant physiological advantages rooted in the anatomy and function of the nasal passages.

• Air Filtration: The nasal hairs (cilia) and mucous membranes act as a primary filter, trapping dust, pollen, and other airborne particles before they reach your lungs. This reduces the burden on your respiratory system and minimizes irritation.
• Air Humidification and Warming: As air passes through the nasal cavity, it is warmed to body temperature and humidified. This prevents the drying and cooling of the delicate lung tissues, which can otherwise lead to irritation, bronchospasm, and exercise-induced asthma, especially in cold or dry environments.
• Nitric Oxide Production: The paranasal sinuses produce nitric oxide (NO), a powerful vasodilator. When you inhale through your nose, this NO is carried into the lungs, where it helps to dilate the blood vessels, improving blood flow and oxygen delivery to the working muscles. NO also plays a role in immune function and neurotransmission.
• Increased Lung Volume and Diaphragmatic Breathing: Nasal breathing naturally encourages deeper, more diaphragmatic breathing. This engages the diaphragm, the primary muscle of respiration, more effectively, leading to more efficient oxygen intake and carbon dioxide expulsion. Deeper breaths utilize more of the lung capacity, including the lower lobes, which are rich in blood supply.
• Parasympathetic Nervous System Activation: Nasal breathing is associated with the activation of the parasympathetic nervous system, promoting a calmer, more relaxed state. This can help regulate heart rate and conserve energy, which is beneficial for endurance activities.
• Improved Oxygen Extraction (Bohr Effect): While not direct, the slower, deeper breaths characteristic of nasal breathing can lead to a slight increase in CO2 levels in the blood, which facilitates the release of oxygen from hemoglobin to the tissues (Bohr effect).

Limitations: The primary drawback of nasal breathing is the higher resistance it offers compared to mouth breathing. The smaller nasal passages make it more challenging to move large volumes of air quickly, making it difficult to sustain during high-intensity exercise where oxygen demand is maximal.

The Case for Oral Breathing (Mouth Breathing)

While nasal breathing offers significant advantages, mouth breathing becomes a crucial component of respiration during certain exercise intensities.

• Greater Airflow and Lower Resistance: The oral cavity provides a much wider, less restrictive pathway for air. This allows for rapid and large volumes of air to be inhaled and exhaled quickly, which is essential when the body's oxygen demand spikes during high-intensity efforts.
• Necessary for High-Intensity Exercise: During maximal efforts, such as sprinting, interval training, or running uphill quickly, the body simply cannot take in enough oxygen through the nose alone to meet metabolic demands. Mouth breathing becomes physiologically necessary to prevent oxygen debt and maintain performance.

Drawbacks:

• Reduced Filtration and Conditioning: Air inhaled through the mouth bypasses the natural filtration, warming, and humidifying mechanisms of the nose. This means colder, drier, and unfiltered air reaches the lungs, potentially leading to airway irritation, dryness, and a greater risk of respiratory infections.
• Potential for Hyperventilation: Shallow, rapid mouth breathing can sometimes lead to over-breathing (hyperventilation), which can disrupt the balance of oxygen and carbon dioxide in the blood, potentially causing lightheadedness or dizziness.
• Sympathetic Nervous System Activation: Oral breathing tends to be associated with the sympathetic nervous system ("fight or flight" response), which can elevate heart rate and may not be ideal for sustained, steady-state efforts.

When to Use Which Method

The optimal breathing strategy for running isn't an "either/or" but rather a "both/and" approach, dictated by your intensity level.

• Low-to-Moderate Intensity (Conversational Pace): For easy runs, warm-ups, cool-downs, or long-distance efforts where you can comfortably hold a conversation, prioritize nasal breathing. This allows you to reap the benefits of air conditioning, nitric oxide production, and efficient diaphragmatic breathing.
• High Intensity (Threshold, Intervals, Sprints): As your pace increases and you cross your aerobic threshold, your oxygen demand will outstrip the capacity of nasal breathing. At this point, opening your mouth and utilizing oral breathing becomes essential to take in sufficient oxygen and expel carbon dioxide rapidly. You'll naturally find yourself using a combination of nose and mouth breathing, or predominantly mouth breathing.
• Transition: Many runners naturally transition from nasal breathing at the start of a run to a mix of nasal and oral breathing as intensity increases. Pay attention to your body's signals and allow your breathing to adapt to the demands of the effort.

Training Your Breathing for Running

You can train your respiratory system to become more efficient, regardless of the method you employ.

• Practice Nasal Breathing Daily: Incorporate nasal breathing into your daily life – during walks, while working, or even during light household chores. This strengthens the muscles involved in nasal breathing and makes it more natural during exercise.
• Warm-up with Nasal Breathing: Begin your runs with 5-10 minutes of strict nasal breathing, even if it means running at a slightly slower pace. This prepares your respiratory system and encourages diaphragmatic engagement.
• Gradual Progression: If you're new to nasal breathing during exercise, start with very short intervals at low intensity and gradually increase duration as your body adapts.
• Focus on Diaphragmatic Breathing: Regardless of whether you're using your nose or mouth, strive for deep, belly breaths rather than shallow, chest breaths. Place one hand on your chest and one on your belly; the hand on your belly should rise more with each inhale.
• Rhythmic Breathing: Sync your breathing with your footsteps (e.g., inhale for 2-3 steps, exhale for 2-3 steps). This can help regulate your pace and ensure consistent oxygen delivery.

Key Takeaways and Practical Advice

• Nasal breathing is superior for conditioning inhaled air and promoting physiological efficiency at lower intensities. It's your best choice for easy runs and building aerobic base.
• Oral breathing is a necessity for meeting high oxygen demands during intense efforts. Don't fight it when your body needs more air quickly.
• Listen to your body. Your breathing pattern should feel natural and sustainable for the intensity you're maintaining. Forcing one method over another when it's not appropriate for the effort level can lead to discomfort or reduced performance.
• Practice makes perfect. Consciously working on your breathing technique can improve your running economy and overall comfort.

Conclusion

Neither nasal nor oral breathing is universally "better" for all running scenarios. An informed runner understands the distinct advantages and limitations of each and adapts their breathing strategy to the specific demands of their workout. By leveraging the benefits of nasal breathing for efficiency and the capacity of oral breathing for power, you can optimize your respiratory function, enhance your performance, and improve your overall running experience.