Back in the day I did an Outward Bound course - very physically intense - and my period was late. I was freaked at first and worried that the birth control had failed and I was pregnant but it was just the intense exercise that delayed it.

I remember when I do extra exercise + stress, it changes my cycle. it can change as much as 1 week late or period comes twice a month. I hated that!

9:28 I learned the hard way that a rogue period when going through menopause needs to be reported to your gyn. She was quite upset with me during annual exam when I said I had had one. Sent me out for transvaginal and sure emough I had an ovarian cyst. We are now monitoring it for growth changes and malignancy.

LOL thanks

So duh, try a pilates class! See what happens! seriously !

The only experience I have with period and exercise is: when I do an intense yoga or pilates class it can bring on menses. Like, last week - i am old (49) and i had not had a period in like, 6-8 months and I did an intense pilates class and it brought on menses! I would have been more shocked but in the past (10 years ago), an intense yoga class did the same thing (the teacher said "you must be ready for big changes...").

So while it's not your exact experience, I do believe that intense exercise and affect your period. Don't be worried -- keep up the good work! Protect your feet/ankles/knees with lots of stretching and good shoes!

So over the last year I have lost about 50 pounds. But I am far from thin - 5 foot four and 160.

I have been doing cardio daily for the last month, I'm up to an hour on the elliptical now. I was running really hard but lately I'm staying in the fat burning zone, HR 142 ish.

My period is late. My period is NEVER late. But I haven't had sex in like three years (see the part where I was fat) so I know I'm not pregnant.

Even though I still have ample body fat, do you think it's possible that the frequent cardio is causing amenorrhea (absence of menstruation)?

Please let me know if you have any experience with this. Thanks!