This article from the NYT last month is one I thought was particularly interesting. I emailed it to my husband but forgot to post to the link to it on the blog in during all the chaos that was Vegan MoFo.
If you don’t want to read the article the bottom line is that strenuous exercise suppresses the immune system but moderate exercise seems to stimulate the immune system. This coincides with other things that I have read that suggest that something as simple as a brisk 10 minute walk can increase the your natural killer cell numbers and activity. According to this abstract the increase happens after 6 minutes. Prior studies have shown the increase in natural killer cells has dissipated 3 hours after the activity has ended.
I think this is a good reason to get up from our computers at least every three hours and take a brisk 10 minute walk. While these quick spurts of exercise may not prevent the flu or cancer, but it certainly can’t hurt. If nothing else, it feels good to get up and move around.