We dont 'catch' a cold .. we invite a cold.

From an Ayurvedic perspective, we get colds for a few reasons:
-our immunity decreases
-our sinues and mucus membrances become dry or irritated
-there is an excess of Kapha in our system due to diet
-due to poor digestion, Ama is not being properly released

Lets look at these.

When we do not get enough rest, become stressed out, dont eat properly or are depressed, our immunity suffers. And when that happens, viruses are free to grow in the respiratory system.

During the winter our mucus membranes become dry due to both cold and electric heat. This too can make us more susceptible to viruses.

During the winter, eating too many cold foods, fried foods, cheese, eggs, and foods made with white flour, white sugar and shortening, all contribute to a Kapha imbalance. Because mucus develops in the stomach, adding too many Kapha elements causes that mucus to spread into the lymphatic and circulatory systems. After that, their next stop is the respiratory system, which becomes filled with mucus and so a breeding ground for bacterial infection.

Ama is "impurity" and is created by overeating or eating too quickly (on the go), or eating when anxious (nervous eating, emotional eating). This impacts the digestive system causing it to become unstable. When that happens, toxicity rises, and left unchecked, can pollute the entire body.

Om Peace!
Yogini Valarie Devi
groups.yahoo.com/group/Hamsa_Yogashala