A cough is more than just an annoying reflex—it’s the body’s defense mechanism against foreign particles and potential threats in the airways. But why does the cough often linger long after we’ve recovered? Research points to a surprising explanation: the infection’s impact on the nervous system.
Coughing – The Body’s Alarm System
Coughing is triggered by nerves in the airways equipped with receptors that respond to various stimuli, from cold air to capsaicin, the spicy compound in chili peppers. When these receptors detect an irritant, they send signals to the brain, which then decides whether a cough is necessary.
However, many people continue coughing even after their infection has cleared. Scientists are still searching for a definitive answer, but they have uncovered a key mechanism: inflammation and hypersensitive nerves.
Inflammation and Hypersensitive Nerves
When we get sick, viral infections provoke an inflammatory response in the body that can make the nerves in our airways hypersensitive. This heightened sensitivity can persist for weeks, causing coughing from even minor irritations, such as cold air or laughter.
A 2016 study found that even dead viruses—neutralized with UV light—could increase the number of TRPV1 receptors in lab-grown human cells. These receptors respond to irritants and can make something as simple as a deep breath trigger a cough. This suggests that it’s not necessarily the active virus itself but rather the traces it leaves behind that can prolong the cough.
How Long Does a Cough Last?
According to experts like Michael Shiloh from UT Southwestern Medical Center, a cough typically resolves within two to three weeks. However, in some cases, it can persist for up to eight weeks—or even longer.
If a cough lasts this long or is accompanied by symptoms such as fever, bloody phlegm, weight loss, or shortness of breath, medical attention should be sought.
This article is based on information from National Geographic.