When having a "natural killer" is a good thing

NK cells, Mother Nature's assasins

The thing about colds is that you can sense they're coming long before they arrive. Colds often start with a scratchy throat that turns into the sniffles, a cough, and a bunch of other fun symptoms. The oft-quoted phrase is, "Three days coming, three days staying and three days going." After I started taking a daily multivitamin in the early '90's, I got far fewer colds. But when I did, they would be intense.

Since I started running in the fall of 2008, the intensity of my colds has dropped noticeably. With the exception of my pneumonia experience, I can't remember feeling particularly ill for more than a day in the past four years. According to WebMD, "Regular exercise appears to have the advantage of being able to jump-start the immune system, and that can help reduce the number of colds you get." The site says that "With exercise...natural killer cells, increase by as much as 50% to 300%."

I plowed through a couple of hard runs over the weekend despite my symptoms, and the intensity of this cold has not increased past the "mildly distracting" stage. I do believe there is something to this "natural killer cell" theory promoted by my running. Despite the name, it's a great concept.