To sleep well and to sleep long enough is important to acquire new knowledge. When we sleep, our brain is “washed” of toxins that accumulate through the day, while neurons and connections in the brain increase. When a person is uncertain of something and says “I’ll need to sleep on this”, it does not simply mean that they need to let the stuff rest for a while to let the brain work on it. When we sleep, we actually – through the creation and increase of new neurons – process, work on and make the new knowledge we gained through the day “stick“.
It’s important to prioritize getting enough sleep, not only in periods with many exams, but also generally in life. It can be tempting to spend many hours every night for a long period before an exam, but lack of sleep does not only make us lose energy and feel tired, it also reduces our ability to learn.
It’s not necessarily damaging to sleep less over a shorter period of time, but for the brain to function optimally, sleep is a prerequisite. For that reason, prioritize getting enough sleep the night before the exam.