Semi tangential, but a friend of mine hit a parked car on a bicycle, thought nothing of it went home, ate a pot of paella and then went to sleep.

Woke up in excruciating pain, went to hospital and nearly died.

Turned out he'd perforated his colon extremely badly, and you only find out those sorts of injuries if your digestive system starts operating, pumping your last meal into your body.

They had to remove all the muck out of his body, and then he spent a few months on fluids and losing a lot of weight.

I guess the lesson is, cycling injuries are often the type of body injuries that take some time to identify. Keep an eye out.