How do I keep myself awake during lectures?

My first year at university is here. And there's this thing: My lectures are sooooooo long. When I try to keep my attention, I start getting very sleepy like 1 hour in. I take notes and everything, I react when teacher asks something, but it doesn't help.

I find this whole situation unnecessary and weird, because it's a natural response to low activity. I don't do anything I go to eep. X_X

How do you keep up? Is there even a way?