Will Qigong eradicate colds from the planet.
Highly unlikely.
Will people who practice Qigong get fewer colds? Probably.
Will a person who practices Qigong and gets a cold recover more quickly? Probably.
I started practicing Qigong in the fall of 1997 and had zero colds, sniffles, or other symptoms until last month. I came down with a cold. My initial response was disbelief. I didn't think of it that much, however, because I was symptom-free within a few days.
