Hi,
I am not Cathe, but I have heard/read several times over the years that if the cold is confined to the neck and above (a.k.a. head, nose, and/or throat), it's ok to work out as you normally would; however, if it is below the neck (a.k.a. in the chest) some *light* exercise may be OK, but do not overdo it. And as always, if you start feeling light-headed, dizzy, weak, etc., STOP. Just pace yourself and listen to your body.
Personally, I think working out when I am sick makes me get better faster! When I don't work out, my body seems to just kind of go into "shut down mode" and isn't moving the germs along fast enough. This could just be psychological, but I can say that the best way that works for me to get rid of a cold is a HARD workout...as soon as I start to feel under the weather, I sweat myself out like crazy and the next day the cold is almost gone!
