Running: How We Breathe During Exercise

How Do We Breathe When We Run?

When running, our body significantly increases its respiratory rate and depth to meet the heightened demand for oxygen, primarily relying on the diaphragm and intercostal muscles, with accessory muscles assisting at higher intensities to facilitate rapid and efficient gas exchange.

The Mechanics of Respiration During Running

Running is a metabolically demanding activity that requires a continuous and ample supply of oxygen to fuel working muscles, while simultaneously necessitating the efficient expulsion of carbon dioxide, a metabolic waste product. The respiratory system, comprising the lungs, airways, and respiratory muscles, orchestrates this vital gas exchange.

At rest, our breathing is largely subconscious and relatively shallow. However, the moment we begin to run, our muscles' demand for ATP (adenosine triphosphate) increases dramatically. This increased metabolic activity leads to:

• Higher Oxygen Consumption: Muscles require more oxygen for aerobic respiration.
• Increased Carbon Dioxide Production: As a byproduct of energy metabolism, CO2 levels rise in the blood.
• Changes in Blood pH: Lactic acid accumulation, particularly at higher intensities, can lower blood pH, triggering a further increase in ventilation.

In response, the nervous system signals the respiratory centers in the brainstem to increase both the ventilatory rate (breaths per minute) and tidal volume (the volume of air inhaled or exhaled with each breath). This adaptive response ensures that the lungs can take in more oxygen and expel more carbon dioxide per minute, maintaining physiological homeostasis.

The Role of the Diaphragm and Accessory Muscles

Efficient breathing during running relies on a coordinated effort of several muscle groups.

• The Diaphragm: This dome-shaped muscle located at the base of the chest cavity is the primary muscle of inspiration. When it contracts, it flattens and moves downwards, increasing the vertical dimension of the thoracic cavity. This creates negative pressure within the lungs, drawing air in.
• External Intercostals: These muscles, located between the ribs, contract to pull the rib cage upwards and outwards, further expanding the thoracic cavity and assisting in inhalation.
• Accessory Muscles of Inspiration: As running intensity increases and the demand for air becomes more urgent, the body recruits additional muscles to assist with forceful inhalation. These include:
  • Sternocleidomastoid and Scalenes: Located in the neck, they elevate the sternum and upper ribs.
  • Pectoralis Minor and Serratus Anterior: These muscles, attached to the rib cage, can also aid in elevating the ribs when the shoulder girdle is stabilized.

Exhalation during light running is largely a passive process, resulting from the relaxation of the inspiratory muscles and the elastic recoil of the lungs and chest wall. However, during hard running, exhalation becomes an active process, driven by:

• Internal Intercostals: These muscles pull the rib cage downwards and inwards.
• Abdominal Muscles (e.g., Rectus Abdominis, Obliques): Their contraction pushes the diaphragm upwards, forcefully expelling air from the lungs. This active exhalation is crucial for emptying the lungs more completely, making space for a larger volume of fresh, oxygen-rich air with the next inhalation.

Breathing Patterns and Intensity

The way we breathe changes significantly with running intensity:

• Low to Moderate Intensity: At this level, breathing is typically rhythmic and controlled. Many runners find a natural rhythm, such as inhaling for two or three steps and exhaling for two or three steps (e.g., a 2:2 or 3:2 ratio). Nasal breathing may be possible, which warms and filters the air, but mouth breathing often becomes necessary to move larger volumes of air. Diaphragmatic breathing (belly breathing), where the abdomen expands with each inhale, is the most efficient method, maximizing lung capacity.
• High Intensity (Anaerobic Threshold and Beyond): As intensity increases, breathing becomes faster, deeper, and more labored. The body shifts from primarily aerobic metabolism to incorporating more anaerobic pathways, leading to increased lactate production and a greater drive to expel CO2. Mouth breathing becomes essential for rapid air exchange. The accessory muscles of inspiration and the abdominal muscles for forced exhalation are heavily recruited. The rhythm may become less consistent, and breathing can feel like gasping.

Oxygen Debt and EPOC

When we begin to run, especially at higher intensities, our body's immediate oxygen supply cannot meet the sudden increase in demand. This creates an oxygen deficit. After we stop running, our breathing remains elevated for a period, even though the immediate muscular demand has ceased. This phenomenon is known as Excess Post-exercise Oxygen Consumption (EPOC), often referred to as the "afterburn effect" or "oxygen debt repayment."

EPOC serves several crucial functions:

• Replenishing ATP and Creatine Phosphate stores: Rebuilding immediate energy reserves.
• Converting Lactic Acid to Glucose: Processing metabolic byproducts.
• Re-saturating Myoglobin and Hemoglobin with Oxygen: Replenishing oxygen stores in muscles and blood.
• Supporting Elevated Body Temperature and Metabolic Rate: The body continues to work to return to its pre-exercise state.

Optimizing Your Running Breath

While breathing is largely automatic, conscious practice can enhance its efficiency and comfort during running.

• Practice Diaphragmatic Breathing: Lie on your back with one hand on your chest and one on your abdomen. As you inhale, focus on expanding your abdomen, ensuring your chest moves minimally. This trains the diaphragm to be the primary mover.
• Focus on Exhalation: Many runners focus too much on inhaling. A complete, forceful exhalation is critical to expel stale air and create space for a full, fresh breath. Imagine "squeezing" the air out with your abdominal muscles.
• Experiment with Rhythmic Breathing: Synchronizing your breath with your footfalls can help establish a natural rhythm and distribute impact forces, potentially reducing the risk of side stitches. Common patterns include a 3:2 ratio (inhale for 3 steps, exhale for 2) for moderate pace, or 2:1 for harder efforts.
• Stay Relaxed: Tension in the shoulders and neck can restrict the movement of the rib cage and diaphragm, making breathing less efficient. Consciously relax your upper body.
• Listen to Your Body: Your breathing rate and depth are excellent indicators of your effort level. Adjust your pace to maintain a comfortable, controlled breathing rhythm that matches your current fitness and goal.

Common Breathing Challenges and Solutions

• Side Stitches (Exercise-Related Transient Abdominal Pain - ETAP): These sharp pains, often just below the rib cage, are common. While the exact cause is debated (possible diaphragm spasms, irritation of abdominal lining, or inadequate blood flow), solutions include:
  • Slowing down and focusing on deep, diaphragmatic breaths.
  • Pressing on the painful area.
  • Stretching by raising the arm on the affected side overhead or bending away from the stitch.
• Breathlessness/Hyperventilation: Feeling like you can't get enough air, or breathing too rapidly. This often occurs when starting too fast or pushing beyond current fitness.
  • Slow down your pace.
  • Focus on controlled, full exhalations to regulate breath.
• Exercise-Induced Bronchoconstriction (EIB) / Asthma: For individuals with asthma or EIB, cold, dry air or allergens can trigger airway narrowing.
  • Always consult a healthcare professional for diagnosis and management.
  • Use prescribed inhalers as directed.
  • Warm-up adequately and consider covering your mouth and nose in cold weather.

Conclusion

Breathing during running is a complex yet highly adaptive physiological process, driven by the body's increased metabolic demands. Understanding the roles of the diaphragm and accessory muscles, recognizing how breathing patterns shift with intensity, and actively practicing efficient breathing techniques can significantly enhance your running performance, endurance, and overall comfort. While largely an involuntary act, optimal respiratory mechanics are a trainable skill that can elevate any runner's experience.