Studying is almost synonymous with all-nighters -- bleary-eyed with tiredness and lack of sleep, on your sixth cup of coffee, you are struggling to pound out that 15-page paper due at 9 am. Sounds familiar? Everyone has done it.
Unfortunately, the latest scientific research on how our brain works shows that cramming all-night for a test, and learning on chronic low levels of sleep, not only hampers our productivity in the short-term, it affects our memory in the long run - we cannot remember what we learned even a few weeks later.
As we sleep, our brains make sense of all the information that we gathered overnight; sorting, creating connections between concepts that we already understand. During cycles of deep or slow wave sleep, we “replay” the activity from the day, deciding what is important and what can be discarded, and then creating connections between the important information and the knowledge we already possess. Unless you get sufficient sleep, what you're learning won’t be consolidated, because it can only be done while our conscious processes are halted. You won’t be able to remember what you need, or learn new things quite as fast if you're always sleep-deprived.
This is another reason why it’s a good idea to spread your studying out over time, instead of concentrating it all over a few days or hours. If you learn a little of a subject at a time, it has time to be processed, and labelled for easy retrieval later when you need it.
Studies even show that sleeping within four hours of learning a new skill is most effective. Sleep, especially the deep cycles of REM (rapid eye movement) sleep, when we dream, consolidates all the information processed through the day, throwing out anything that made faint impressions or that the brain deems irrelevant. This sort of house-keeping is important for everyone, but it is especially crucial when trying to create new skills or learn new subjects.
In recent years, research has found yet another reason why we need adequate and regular sleep. The brain generates toxin build-up, just like the rest of the body does. The brain’s own cleaning department, the cerebrospinal fluid, can only perform its toxin removal tasks at night. Without this process, waste products builds up, which are harmful to brain cells and impair normal cognitive processing. This explains why on days when we don’t get sufficient sleep, we feel increasingly sluggish and tired, and can’t think as clearly.
One way to improve your learning and catch up on sleep is to have a short 20 - 40 minute nap. Naps can be powerful strategies to reboot the system when you're feeling particularly exhausted – something even corporate executives are slowly discovering - but we often feel guilty or silly taking a nap, maybe because naps remind us of being in kindergarten. Many famous creative people throughout history took short daily naps – William Faulkner, Ayn Rand, Buckminster Fuller and even Stephen King, probably because they too discovered that you can be even more creative if you’re fully rested.