Exercise and Your Immune System Revisited

It's not every day I get an email from someone in Taiwan about exercise, white blood cells, and menstruation. But in response to my post How Much Exercise Harms Your Immune System?, Guan-Da Syu from National Cheng Kung University Medical College dropped me a friendly note (if you can call an email with its own bibliography a "note") a few days ago. Syu is the lead author of the paper I'd discussed in that post, and he wanted to respond to some questions I raised.