One of the best things you can do to get healthy when you’re experiencing cold and flu symptoms is to learn what your common cold symptoms are trying to tell you.
The Stuffy Nose: What the Nose Really Knows
A “stuffy” nose, often the most irritating symptom of the common cold, is caused by localised inflammation of the lining of the nose and dilation (widening) of tiny blood vessels, which restricts airflow in the nose. “This may in fact be an attempt by the body’s immune system to raise the temperature within the nose, creating a hostile environment which may affect how successfully the viruses can replicate,” says Professor Ron Eccles, founder and Director of the Common Cold Centre, Cardiff University. Mucus in the nose and airway is the first line of defence against infection. Nose secretions may also change in colour when an individual has a cold, with the colour intensity increasing as the cold progresses due to the volume and increased activity of immune defence cells and proteins.1 If you’re having a hard time breathing due to a stuffy nose, a decongestant nasal spray or capsules can often provide quick relief (always read the label for correct usage instructions).
Coughing: Another Bothersome Symptom of the Common Cold
Coughs exist to ensure the lungs remain clear of mucus and inhaled particles so that they can do their job of providing oxygen to the blood stream. Colds induce coughing by causing inflammation around the nerve endings in the throat and airways. This causes a hypersensitivity of the normal cough reflex.1 A cough can be productive (“wet”) or unproductive (“dry”). A productive cough expels secretions from the respiratory tract that, if retained, could impair normal ventilation and the lungs’ ability to resist infection. An unproductive cough is typically stimulated by a mechanical irritant or other type of irritant and serves no useful physiological purpose.2 Although coughs can help your body rid itself of harmful secretions, dry tickly coughs can often be a nuisance if you’re at work or just busy trying to live your life. A cold medicine for dry or tickly cough in the form of a syrup or throat lozenges may be able to help soothe the throat and calm the cough reflex.
The Surprisingly Mighty Sneeze
Sneezing is a protective reflex that occurs when foreign matter or external stimulants reach the nasal mucosa. This triggers the release of histamines, which irritate the nerve cells in the nose, resulting in signals being sent to the brain through the trigeminal nerve network. Nerve signals are then sent back to the nasal glands, facial muscles, and respiratory muscles, resulting in a powerful release of air (the velocity of air discharge can range up to 100 metres per second, 10 times faster than an Olympic sprinter). Often, other protective reflexes such as tearing and closing of the eyes occur in order to protect the nose and eyes from irritants. 3,4,5
The Source of Your Common Cold Symptoms
Cold viruses attack the upper respiratory tract, but they can sometimes also infect the bronchial tubes, the eyes, and the middle ear. Common cold symptoms are not triggered by the viruses themselves, but by the defensive reaction of the body's immune system. The body deploys immune cells and antibodies to destroy the invading virus. Unfortunately in most instances these reactions are an overreaction to the common cold virus – making you feel much more miserable than you need to feel.
For example:
Your runny nose may be due to your body trying to quickly move fluids to the site of infection in order to help flush away the virus and damaged respiratory tract cells.6
Your stuffy nose may be a result of inflammation caused by release of immune system messenger proteins called bradykinins.1
Your scratchy throat may be due to localised inflammation also caused by these immune system messenger proteins.1
1 Eccles, R. Understanding the symptoms of the common cold and influenza. Lancet Infect Dis, 2005; 5: 718–725. 2005.
2 American Pharmacists Association®, Nurse Practitioner Healthcare Foundation, American Academy of Physician Assistants. Self-Care for Fever, Cough, Cold, and Allergy. OTC Advisor: Advancing Patient Self-Care. 2007.
3 Muether, P.S., et al. Variant Effect of First- and Second-Generation Antihistamines as Clues to Their Mechanism of Action on the Sneeze Reflex in the Common Cold. Clinical Infectious Diseases. 33. 2001.
4 King, et al. Clearance of mucus by simulated cough. Journal of Applied Physiology. 58(6):1776-1782. 1985.
5 Quraishi, M.S. The rheology of nasal mucus: A Review. Clinical Otolaryngology. 23:403-413. 1998.
6 Cate, T.R., Rossen, R.D., Douglas, R.G., Butler, W.T., Couch, R.B. The Role of Nasal Secretion and Serum Antibody in the Rhinovirus Common Cold, American Journal of Epidemiology. 1966;84(2).