I started up again maybe 4 months pp. But that had nothing to do with feeling well enough to start again. It was more I just didn't have the time in the morning or evening when my husband was around, and I'm not a fan of running with a jogger. So it was really about carving out the free time. But if you're feeling well enough and had a straightforward birth that doesn't require any extra healing time, I'd start up again within a month or so. (Though me personally, I always prioritise sleep over exercise, so I'd be using that time for a nap instead until I felt caught up on my sleep again!).