So, on page 142 of his book he tackles the question "Should you exercise with a cold?" head-on noting that what you do in the six hours following a hard workout (or race) is critical to your overall health.
He reasserts what I posted before, in that your immune system takes a big hit when you expend so much energy exercising so immediately following any workout, it's best to avoid people and public places (kinda hard in a post-race environment, no?) This could explain why, in a study of entrants to the LA Marathon that Friel cites, "runners who completed the marathon were six as likely to be ill the week following the race as those who registered but did not show up."
So, how do you proceed when you're in a situation like mine (feeling the cold/flu coming on)? Friel recommends a "neck check":
If you have above-the-neck symptoms, such as a runny nose or scratchy throat, start your workout, but reduce the intensity and duration. you may begin to feel better once you're warmend up, but if not, stop. If the symptoms are below the neck -- such as a sore throat, chest cold, chills, coughing up matter, achy muscles, or a fever -- don't even start. These are often the symptoms of a virus. Exercising will make it worse.And the kicker? Even after the bad part of your flu is over, your performance suffers for a long time, anywhere from a month to three months, depending on how bad your flu was. Ugh
Oh, please let these be allergies.