I think one needs to be careful about truly pushing limits when sick... the sick body is in imbalance. To get anywhere near a properly defined "limit" means pushing the system to the edge of a failure mode. Or multiple ones. A sick body is much less predictable, and enzymatic or electrolyte or mineral imbalances could be literally dangerous-- if pushed to limits.

That said- I ride sick. I climb sick. In the end, I believe that I'm STRONG and that my body, and immune system, are fairly invincible.

Yes I know that's not true. But it's a good head space to carry around.