A recent study shows that napping before an exam is just as effective as cramming at the last minute. According to Jessica at New Scientist, “napping is just as effective as revising, and could even have a longer-lasting impact.”
For this study, 72 volunteers sat through an 80 minute lecture about different species of ants and crabs. After the presentation, they were given the opportunity to either take a 1 hour nap, or watch an informative video on the subject. Those that took the nap ended up scoring higher on a 360 question exam given after another 80 minute lecture following their nap.
If you are going to attempt to take a nap before your exam to try this out, make sure you set at LEAST a couple of alarms. You never know when that 45 minute to an hour nap could lead you to missing your exam.
Source: Napping before an exam is as good for your memory as cramming | New Scientist