Used to have weekly migraines. Then, started drinking my Imperial weight (150 lbs) in Imperial ounces of water (150 ounces). Haven't had a migraine since!
Of course water intake requirements depend on sex, body size, activity level, climate, and amount of water consumed from other sources. Headline is incorrect, SOME people will need to drink 8 cups, maybe that is you. Some will need to drink more.