[gjm11]

> Lead researcher Dr David Nieman and his team, from Appalachian State University in North Carolina, say bouts of exercise spark a temporary rise in immune system cells circulating around the body that can attack foreign invaders.

This makes an interesting contrast with other recent reporting on colds and the immune system, such as http://www.nytimes.com/2010/10/05/opinion/05ackerman.html?_r... which says (correctly, AIUI) that the immediate cause of cold symptoms isn't the infection itself but the body's immune response to it.

Resolution: http://blogs.plos.org/bodypolitic/2010/10/06/how-not-to-figh... -- a more active immune system at the moment of possible infection may help you not get infected, but a more active immune system while you've got the infection may make things worse. (And: "the immune system" is a complicated thing, and the bits of it that make a cold worse may not be the same as the bits that make you less likely to get one.)

[jonhendry]

That probably means it's a good idea to not exert yourself once the cold has hit.