1) you have more running clothes than normal clothes in your laundry pile.
2) you no longer hate portaloos. In fact, there have been times when you've been very happy to see one!
3) one of the first things people ask you when they haven't seen you for a while is, 'What race are you training for now?'
4) you want to cry or punch your doctor in the face when he tells you that you can't run for two weeks.
5) the only time that major household chores get done is during tapering or race recovery.
6) you know how to correctly spell and pronounce 'plantar fasciitis'.