sometimes it's not the 'flu though - could just be a common allergy that causes a runny nose, but in stead of shaking it off like it usually does (if your immune system is in place), it becomes an infection and moves down to your lungs. my own totally unscientific theory goes like this: after you trained, your body needs to concentrate on recovery, and it doesn't multitask that well, so while it's recovering, it lets the guard down a little bit, so when there's an allergy or an irritation or a mild flu strain, the defense system don't pay attention (cos it's busy somewhere else), and you get sick. my own totally unscientific solution is to just rest inbetween training sessions (like teh-runner said) ... and helping it by adding some multivitamins won't harm ... or african potato, garlic and lemon (the last bit of unscientific theory i heard somewhere else, though)
