Thanks Parkfell, I currently have a suspected injury so it will be a while since I can start up again. Before the suspected injury I was running 5k every other day and got my time down to just over 20 minutes.
Depending on how it all pans out I may be able to resume heavy exercise using a cross-trainer and exercise bike much sooner than running, though I'm aware that the pulmonary benefits aren't quite in the same league.