Having a cough can protect your lungs, but sometimes it seems to linger after illness. Here’s how to get rid of a stubborn one.
While coughing itself is not a disease, it is widely recognized as a symptom that is difficult to alleviate. Why do we sometimes cough persistently?
Coughing Cleanses Your Body
“Cough very much is a natural and protective thing; it protects our lungs,” Dr. Kian Fan Chung, a professor at the National Heart & Lung Institute at the Imperial College London, told The Epoch Times.
“It is a bit like a burglar alarm you have at home,” Dr. Chung said, conjuring a vivid analogy. “So if a burglar does go into your home, the alarm system goes up.”
The respiratory tract is abundant in nerve endings, some of which are known as cough receptors, located in the throat, vocal cords, and upper airway of the lungs. They react to foreign substances and stimuli; when activated, they trigger the cough reflex to expel mucus or foreign objects.
When we cough, we often gasp deeply, allowing air to penetrate the lungs. Following this, the glottis closes, covering the airway, while muscles in the chest and abdomen contract forcefully. At this point, air trapped in the airway cannot escape, resulting in significant intrathoracic pressure, typically exceeding 300 millimeters of mercury (mm/Hg). Finally, the glottis suddenly opens, causing air to rush out at speeds of up to 50 miles per hour, carrying mucus and foreign particles away from the airways. During vigorous coughing, the air expulsion approaches the speed of sound.
Viral or bacterial infections, chemical toxins, inflammation, allergies, mucus in the nose, and stomach acid can all stimulate cough receptors. Moreover, apart from the respiratory tract, various sensory receptors are located in the ears, nose, stomach, pleura, pericardium, and other areas, all capable of triggering the coughing reflex.
Acute Coughs Are Typically Self-Resolving
Coughs are classified as one of three types based on the duration of symptoms: acute cough (lasting less than three weeks), subacute cough (lasting three to eight weeks), and chronic cough (lasting over eight weeks).
By Flora Zhao
