Why do we cough when sick
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Understanding Why We Cough When Sick
Coughing is a common symptom experienced during illness, particularly respiratory infections. This article explores the various reasons why we cough when sick, drawing on insights from multiple research studies.
Cough as a Protective Reflex
Cough Reflex Mechanism: Coughing is a protective reflex designed to clear the airways of irritants, pathogens, and secretions. It involves a complex interaction between sensory receptors in the larynx and lower respiratory tract, which send signals to the brainstem via the vagus nerve. This triggers a series of breathing maneuvers resulting in the sudden expulsion of air .
Role of Sensory Receptors: The activation of sensory receptors, particularly C-fibre receptors, leads to the release of neuropeptides such as substance P, which stimulates the cough reflex. This process is crucial for maintaining clear airways and preventing aspiration.
Causes of Cough During Illness
Viral Infections: The most common cause of acute cough is viral infections, such as the common cold. These infections cause direct irritation of the upper airway structures, leading to cough. The inflammation and excess mucus production associated with these infections further exacerbate the cough reflex .
Inflammatory Response: Inflammatory mediators released during infections can directly interact with sensory nerve receptors, inducing a cough response. This inflammation can persist even after the initial infection has cleared, leading to prolonged coughing .
Environmental and Occupational Factors: Exposure to environmental pollutants, allergens, and occupational irritants can also contribute to cough. These factors can cause hypersensitivity responses and chronic conditions such as asthma and hypersensitivity pneumonitis, which are associated with persistent coughing.
Chronic Cough and Its Implications
Chronic Cough: Chronic cough, defined as a cough lasting more than eight weeks, can result from various conditions, including asthma, gastro-oesophageal reflux disease, and chronic obstructive pulmonary disease. Chronic cough is often associated with neuronal hypersensitivity, where the cough reflex becomes overly sensitive to stimuli .
Impact on Quality of Life: Chronic cough can significantly impair quality of life, causing distress and inhibiting normal social activities. Effective management requires addressing the underlying cause and desensitizing the cough pathways .
Conclusion
Coughing when sick is primarily a protective reflex aimed at clearing the airways of irritants and pathogens. It is most commonly triggered by viral infections, which cause direct irritation and inflammation of the respiratory tract. Environmental and occupational factors can also contribute to cough. Understanding the mechanisms and causes of cough is essential for effective management and improving patient quality of life.
Sources and full results
Most relevant research papers on this topic