I'm just wondering about this, because when I drink coffee, sometimes I feel like I can't focus. Is it possible that drinking coffee will limit my ability to grasp mathematical concepts? What is recommended for helping me to get focused? I guess exercise is good, and maybe antioxidents like green tea. I am going to be enrolling in a Calculus class coming up, and would like to be mentally optimal. While I understand that everyone learns differently, I'd like some good advice about what is recommended (mental herbs?), and what to avoid (such as alcohol).