A few years ago I had my first bad case of bronchitis. I was coughing so much and so hard that blood vessels were bursting in my eyes and I was not able to sleep for days in a row. Strong drugs let me sleep that time but the next time it happened I could not get in to see a doctor before it had run its course (and I had already lost sleep). Some internet research turned up that exercise can help turn a common cold into bronchitis. Thinking about it, I realized that this bronchitis did not show up until I had started jogging. So, the next time I had a cold I cut out jogging and no bronchitis...well, at least it wasn't as bad. So far so good until earlier this year when I caught another cold. I was cycling instead of jogging so I cut that out. The cold did turn into bronchitis (not so violent, though) but it stayed around for months. Sigh.
This is the other thing about my training that I worry about: that bronchitis will sideline me for two or even three months. A year is a long time to train and I should be able to absorb even a delay like that but my plan involves a lot of small increases in volume, which a long layoff would really mess with. We shall see.