The Cold Symptom

The Stuffy Nose: What the Nose Really Knows
A "stuffy" nose, often the most irritating symptom of the common cold, is caused by inflammation of the 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 defense against infection. Nose secretions may also change in color when an individual has a cold, with the color intensity increasing as the cold progresses due to the volume and increased activity of immune defense cells and proteins.¹ If you’re having a hard time breathing due to a stuffy nose, a nasal decongestant or nasal spray can often provide quick relief.

Cough: Another Bothersome Symptom
Coughs exist to ensure the sterile environment of the lungs. 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 nonproductive ("dry"). A productive cough expels secretions from the lower respiratory tract that, if retained, could impair ventilation and the lungs’ ability to resist infection. A nonproductive cough is typically stimulated by a mechanical irritant or other type of irritant and serves no useful physiological purpose.² Though coughs can help your body rid itself of harmful secretions, they can often be a nuisance if you’re at work or just busy trying to live your life. A cold medicine with a cough suppressant or cough drops 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. The efferent pathways activate nasal glands, facial muscles, and respiratory muscles, resulting in a powerful release of air (the velocity of air discharge can reach up to 100 meters per second). 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 Cold Symptoms
Cold viruses attack the upper respiratory tract, but they can sometimes also infect the bronchial tubes, the eyes, and the middle ear. 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.

• Your runny nose might be due to your body trying to quickly move fluids containing antiviral particles to the site of infection and flushing away the virus and damaged respiratory tract cells.⁶
• Your stuffy nose might be a result of inflammation caused by the release of immune system messenger proteins called bradykinins.¹
• Your scratchy throat might be due to localized inflammation also caused by these immune system messenger proteins.¹

* Dr. Ron Eccles serves as a paid consultant to Procter & Gamble.