A lot of modern athletes have physical ailments as they get older as a result of the stress placed on their bodies. I would imagine jousting would have a similar effect since it seems brutal, but did jousters(?) do it enough to where it would effect their bodies later in life? And if so, do we have any first hand accounts of this?
This is a great question, so I'm sad to say I've never come across evidence which might allow us to draw up an accurate answer. It should be remembered that, unlike modern athletes, jousters did usually joust for a purpose (although it became more and more redundant as the practice went on). That purpose was, of course, warfare. I'll draw up a hypothetical list of what evidence we would require to make an accurate evaluation of this phenomena:
Narrative or documentary sources which detail who was injured in the tournaments and how.
Bodies! This would allow us to reconstruct injuries which might have occurred from the pursuit of hitting other men with sticks while on horseback.
Narrative or documentary records which detail the rest of these persons life so we can discount possible injuries in other fields (such as normal riding, hitting other men with the intent of killing them, or falling off a bridge).
So I'm afraid to hypothesize that the evidence is simply unlikely to turn up. Unlike rugby players, footballers, or boxers we don't have the documentary culture to provide the requisite sourcebase. Great question though!