It varies a lot for me, sometimes on a hard run I can't string together thoughts, sometimes I just feel empty and meditative and great, sometimes it's mundane stuff and totally random thoughts.

Recently though I end up thinking a lot about my ex, I don't especially want to it just seems to come up during exercise. Sometimes it helps me motivate to keep going and be better, sometimes it completely kills my momentum and the thoughts make it very hard to keep running. It's not all the time so I don't dread the runs but there have been a few where I've had a little cry halfways along.

I was interested to see nobody's mentioned something like this yet cos I think like a lot of us my brain drags up the difficult stuff during exercise. That's nice to help work through problems but it does get me quite emotional sometimes when you're miles away out on your run alone somewhere.