Picture this: you’re sitting in a two-hour lecture, your eyes are heavy, your brain is foggy, and your mind is (literally!) dozing off. You’re struggling to stay awake in class, but of course you don’t want to nod off and miss a section of the lecture — or worse, get caught by the professor. If this scene feels a little too real for you, then you know how hard it can be to stay awake in class. After all, you have a full workload and social life!

There are tons of helpful tips and tricks to stay awake in class, but TBH sleep is non-negotiable. “Your brain runs on sleep, and you will have a big breakdown in mood and learning when you’re not getting enough sleep,” says Roxanne Prichard, PhD, a professor of neuroscience and psychology and sleep expert at the University of St. Thomas. In other words, consistent sleep is necessary for learning. “We have a lot of data that shows if you sleep well, you’re not going to be the one falling asleep in class,” she explains.

Okay, but how much sleep do you actually need? Seven to nine hours per night, Dr. Prichard says. “Consistency is very important and it’s about having a consistent rhythm, so try going to bed and waking up at the same time to get the sleep your body needs.”

But sometimes life happens, and your busy schedule gets in the way. If that’s the case, there’re a handful of simple ways to perk up during class to keep you engaged, alert, and actively learning. Read on for 15 tips from real, busy students on how to stay awake in class.