I started getting them in HS because of cross country. My senior year I didn't have a first period, so after the 6am 5 mile run, I'd take a nap w/o eating or drinking anything. I still get them - exercise makes them worse. I can usually feel them coming if my blood sugar is low (makes it hard to scrub the lbs for racing season when you get a migraine if you don't eat), and I'll sometimes get the blindness in the shower after a ride, mostly b/c I probably didn't eat or drink enough.

Can't tell if caffeine makes them worse, but I certainly have "triggers" I haven't worked out. Mine headaches are the "blind in the middle of my vision" with nausea followed by actual pain. I'll take the pain over the other symptoms anyday.