Light spotting, cramping between periods when i run, possible causes?

I am a 50 yr old female experiencing light spotting, cramping between periods when I run, or w/ heavy exercise. My cycle has been all over the place since my last pap smear/gyn visit 8 months age. Skips a few months, then comes a couple of weeks apart, then spotting when I run.

Is this normal for my age, and what can I do to help regulate these symptoms?

I am active, normal weight and very healthy eater.

Any suggestions?

Thanks