Runners Spitting: Causes, Physiological Responses, and Management

Why Do Runners Spit So Much?

Runners' propensity to spit frequently during exercise is a normal physiological response primarily driven by increased respiratory demands, changes in saliva consistency, and heightened mucus production to protect and clear the airways.

Physiological Responses to Exercise

During strenuous physical activity like running, the body undergoes significant physiological adaptations to meet the increased demand for oxygen and energy. The respiratory system, in particular, works overtime.

• Increased Respiratory Rate and Depth: As exercise intensity rises, runners breathe more rapidly and deeply. This often shifts breathing from primarily nasal to predominantly oral, especially at higher intensities, to maximize air intake.
• Oral Breathing and Airway Drying: Breathing through the mouth, particularly in dry or cold environments, bypasses the natural humidifying and filtering functions of the nasal passages. This can lead to a sensation of dryness in the mouth and throat, stimulating salivary glands to increase production in an attempt to re-lubricate these tissues.
• Sympathetic Nervous System Activation: Exercise activates the sympathetic nervous system (the "fight or flight" response). While this typically reduces overall salivary flow (making saliva thicker and stickier), the perception of increased oral secretions can still occur due to changes in consistency and the body's effort to clear airways.

Understanding Saliva Production

Saliva plays crucial roles in oral health, digestion, and lubrication. During exercise, its production and properties can change.

• Lubrication and Protection: Saliva helps keep the mouth and throat moist, protecting tissues from irritation. When the mouth dries out from increased airflow, the body attempts to compensate by producing more saliva.
• Consistency Changes: The saliva produced during exercise can sometimes become thicker or more viscous. This altered consistency, combined with the increased volume, can make it feel more noticeable and prompt the urge to expel it.

The Role of Mucus and Airway Secretions

Beyond saliva, the respiratory tract itself produces mucus, which is vital for airway health.

• Mucus Function: The lining of the respiratory tract (from the nose down to the lungs) produces mucus to trap inhaled particles such as dust, pollen, pollutants, and microbes. Tiny hair-like structures called cilia then sweep this mucus and trapped debris upwards and out of the airways.
• Exercise-Induced Mucus Production: Increased airflow during running can irritate the respiratory passages, prompting an increase in mucus production as a protective mechanism. This is especially true when breathing cold, dry, or polluted air.
• Post-Nasal Drip: The increased mucus from the nasal passages and sinuses, often exacerbated by exercise, can drip down the back of the throat (post-nasal drip), contributing to the sensation of needing to clear the throat or spit.
• Bronchoconstriction: For some individuals, especially those with exercise-induced bronchoconstriction (EIB) or asthma, exercise can trigger airway narrowing and increased mucus production, further contributing to the need to clear the airways.

Environmental Factors

The environment in which a runner trains significantly influences respiratory responses and, consequently, the urge to spit.

• Cold, Dry Air: Running in cold, dry conditions is particularly irritating to the respiratory tract. The airways work harder to warm and humidify the inhaled air, leading to increased fluid secretion and mucus production. This can make the throat feel scratchy and stimulate coughing or spitting.
• Pollutants and Allergens: Exposure to air pollution, pollen, or other airborne allergens during a run can trigger an inflammatory response in the airways, leading to increased mucus production as the body tries to expel these irritants.
• Humidity: While dry air promotes dryness and mucus, very high humidity can also make breathing feel heavy and contribute to a feeling of congestion, potentially increasing the perceived need to clear the throat.

Psychological and Behavioral Aspects

While primarily physiological, some behavioral components also contribute to spitting during runs.

• Habitual Behavior: For many runners, spitting becomes an ingrained habit, a simple and effective way to clear the mouth and throat without breaking stride or interrupting breathing rhythm.
• Perceived Need for Optimal Breathing: Runners often feel that clearing their airways allows for more efficient and comfortable breathing, even if the actual physiological benefit is minor.
• Social Acceptance (in context): Unlike in many social settings, spitting during intense exercise, particularly in outdoor environments, is generally considered acceptable and understood by fellow athletes.

Is Excessive Spitting a Concern?

In most cases, the spitting observed in runners is a normal, harmless physiological response to the demands of exercise. However, there are instances where it might warrant attention:

• Changes in Mucus Color or Consistency: If the expelled mucus is persistently discolored (green, yellow, or blood-tinged), unusually thick, or accompanied by a foul odor, it could indicate an infection or other underlying respiratory issue.
• Accompanying Symptoms: If excessive spitting is accompanied by persistent coughing, wheezing, shortness of breath, chest pain, or significant fatigue, it's advisable to consult a healthcare professional. These symptoms could point to exercise-induced asthma, bronchitis, or other respiratory conditions.

Managing the Urge

While spitting is largely unavoidable for many runners, some strategies can help manage the sensation:

• Stay Hydrated: Adequate hydration before and during runs helps maintain optimal fluid balance, potentially making secretions less viscous and easier to manage.
• Prioritize Nasal Breathing: Whenever intensity allows, breathing through the nose helps filter, warm, and humidify the air, reducing irritation to the airways.
• Warm-Up Adequately: A gradual warm-up prepares the respiratory system for the demands of exercise, potentially reducing the initial shock and irritation that can lead to excessive mucus production.
• Consider Environmental Factors: If possible, avoid running during peak allergy seasons or in areas with high air pollution. In cold weather, wearing a scarf or buff over the mouth and nose can help warm and humidify inhaled air.

Conclusion

The frequent spitting observed in runners is a multifaceted phenomenon, stemming from the body's remarkable physiological adaptations to the stress of exercise. It's a natural consequence of increased respiratory effort, changes in saliva properties, and the protective mechanisms of the respiratory system working to maintain clear and efficient airways. Understanding these underlying mechanisms can provide comfort that, for most, it's simply a normal part of the running experience.