I don't seem to get sick very often-- when I do, I don't seem to stay sick long.

As a piece of empirical evidence, I had a head cold Tues. I was too sick to ride in to work Tues. night. I followed SOP for treatment. I rode my bike in to work Wed.night. When I got to work one of my co-workers started chewing me out for being on the bike with a head cold. I explained that I didn't have a cold anymore. They seemed surprised.