system
Given the following post, respond as if you're commenting on Reddit:
human
Is coughing an evolutionary advantage? If so, why do we try to suppress it with cough syrup ?

Coughing is the way our body tries to get rid of foreign bodies out of our lungs. I wonder why we should prevent our body to cough, even if it allows us to get rid of some virus. I understand that it slows down the spreading of the disease, however I don't understand, from an evolutionary point of view, why this feature was kept. If it is so disadvantageous, why would this trait survive ? If it's advantageous, why do we suppress it ?
gpt
Coughing does aid in clearing the airways of particulate debris and mucus. It is a reflex mediated in part by the vagus nerve (CN X). However, coughing is violent and forceful and too much can be detrimental. 

In many respiratory viral illnesses, the skin lining the airways is a target and port of entry. These skin cells can slough off the airways and mix with mucus and get coughed out of the lungs. However, when the skin sloughs off, it can expose nerve endings called J-fibers. These J-fibers can stimulate more cough, leading to more skin cells sloughing off and more exposed J-fibers and the process builds on itself in a positive feedback loop. 

Additionally, coughing can be so violent that a person can break ribs, dislocate joints, suffer a pneumothorax or pneumonediastinum, or any number of unintended consequences. 

Suppressing cough is typically done for comfort, and to allow the skin lining to calm down and heal after a viral illness, and to prevent any unwanted sequelae from uncontrolled cough. 

Cough suppression is not without risk however, and can put a person at risk for secondary bacterial pneumonia or any number of other lung diseases. The choice to treat cough is a risk vs benefit calculation.