Ladies ... common to have delayed menstruation when starting vigorous exercise ?
Hmm I have not had that problem but then again I'm exercising moderately rather than very strenuously.
Mine has been delayed the past few months, and I dropped a size in early December pretty quickly. It's also gotten lighter.
I did, however, get a copper IUD about a year ago and it could be that it's readjusting to pre-IUD flow.