Does lifting weights suppress the immune system? I've noticed that ever since I've started lifting, I've gotten sick more often. I'm sure there could be other factors (rest, diet etc) but I was wondering if lifting will cause more of a supression than other factors.

Also, I have been sick the last couple of days, very sore throat and chest congested. I've noticed that after I lift, my congestion clears up really fast. Any ideas why that happens?