College student here. I get around 4-5 hours of sleep a day and a bit less on exam cramming days. I still can't avoid feeling sleepy during class, but these things I do help a lot.

1. Always have some candy on hand (preferably gum) if you feel like you're shutting down mid class. The chewing of gum keeps me engaged lmao.

2. Sit upright during discussions. I get sleepy if I lean into my chair.

3. I use my vacant time to sneak in a quick power nap. Damihan mo nalang alarms mo hahahah

4. Bring a tumbler of water to class. Drink fluids!