I had a half iron distance race last weekend and caught a nasty cold the day before the race. What should have been a perfect race turned into a "getting through it" race. Unfortunately colds happen. You have to assess how bad you are feeling and make a decision from there. If it would have been a training day I would have taken the day off so I could recover from the cold quicker... but since it was the last race of the season I decided to go ahead and race. ...a week later I'm still getting over the cold. Cold season is starting. Make sure to take in your vitamin C and get plenty of rest!!