Why do we Have Certain Symptoms?
The common cold's most basic symptoms are: headache, runny nose, stuffy nose, sore throat, and fatigue.
Headaches - The cold puts a great strain on the body because the body attempts to regain its 'normal' state of being. In result, a great deal of cellular respiration occurs. (Cellular Respiration - the process of breaking down food molecules into cellular energy. ) Cellular respiration occurs because regaining proper body function is difficult without having the sufficient amount of cellular 'fuel.'
One 'step' of cellular respiration requires exhaling water from a cell. Since many cells during a cold go under cellular respiration, a person looses water. Due to the loss of water, the brain (which is 75% water and is sensitive to water levels) sends an alert through the neurons.
On a macro-level, we receive the alert in the form of a headache which is the body's way of telling us that it needs more water.
Runny Nose - When an infected cell becomes numerous in the nose region, it disrupts a person's homeostasis. In an attempt to regain homeostasis, the nose over produces mucus in an attempt to physically 'wipe-out' the virus. It should be noted that a runny nose happens during different times of the duration of a cold because of a certain number of infected cell required in the nose. (Also, the cold virus directly targets the nasal area since colds are defined as an upper respiratory infection.)
Although runny noses are tiring to deal with, the color of the mucus are useful indicators whether or not a person has an infection or merely has allergies. Sneezing white mucus indicates a person is healthy and has no infection. However, green or yellow mucus indicates an infection.
Stuffy Nose - During a cold many of the nasal tissues and pathways become inflamed (in other words, become swollen). Due to the nasal pathways and tissues becoming inflamed, blood circulation in the nose cannot occur. Since circulation cannot occur the nose feels 'clogged' and a person is unable to breathe.
Sore Throat - A sore throat is caused by mucus dripping down the throat. It irritates the throat which causes a person to cough. Since a person coughs many times when they have a cold the throat and vocal muscles are over worked and become sore. In addition, the hurting sensation a person feels when they cough is due to the force of a cough.
Fatigue - Fatigue is usually the result of dehydration which is usually the result of having a cold. With dehydration, blood to move more slowly towards the organs. In result, the slow movement of blood makes a person feel tired and exhausted.
