Yesterday I did back and biceps. I was feeling fine until the end of my routine. I finished off by pyramiding hammer curls and at about my fourth set I got a pounding headache and I mean pounding. I put the dumbbells down and headed for the locker room, rubbing my temples because my brain hurt so much. By the time I got to the shower the headache was completely gone. Weird, eh? Do you think perhaps I wasn't breathing properly or somehow the exercise made my blood pressure rise? Anyone else have this happen?