Should you do qigong while sick?

When I say sick, I mean with an exterior condition (like a cold, the flu, etc.). Salvo #1 comes from an old Daoist document, “Tai Xi Bao Yi Ge” (translation courtesy of Dr. Yang Jwing Ming)
“When Embracing Singularity, (you) must know how to be magnanimous within yourself automatically. (You) must not allow the breathing to [...]