One thing got me through college with (most of) my sanity intact: napping. Whether it was in my apartment or in the library, napping gave me the energy to carry on. Even after graduating, I find a good nap to be immeasurably helpful in energizing me when I need it.

There are three types of napping: planned, emergency and habitual. Planned napping is what I often did between classes—napping to give myself energy before I got exhausted. Emergency napping is more rare: if you’re driving at night and find yourself too tired to drive, pull over and take an emergency nap. Habitual napping is just daily scheduled naps. Napping for 20–30 minutes daily is recommended in order to increase alertness and productivity!

The length of the nap is important! Sleep comes in five stages: Stages 1 and 2 are light sleep, Stages 3 and 4 are deep sleep, and Stage 5 is REM sleep (where most dreaming occurs). Humans cycle through all of the stages in about 90 minutes, so if you have the time, a 90-minute nap can be as beneficial as 8 hours of sleep! If you wake during the deep-sleep stages of a cycle—something that I am often guilty of!—you’re more likely to be groggy and irritable. So if you’re going to nap, nap smart!