We will come to this question later. Just having a little detour: Did you ever remember something, out of nowhere, that you had been trying to remember the day before? Or come up with a great idea while cooking, or running, while you are not purposefully thinking about it? These are not actually rare occurrences, and they are live proofs that our brain is not on a break, even if we think it is!
Years ago, I took a course online called "Learning How To Learn". It is a very interesting course that explains different techniques of learning. Other than the explicit techniques that we can use to learn, it also contains implicit learning techniques. In particular, with the instructor Dr. Barbara Oakley's terminology, "diffuse learning': when our brain continues to process information even when we are unaware of it (1). All the examples I mentioned in the previous paragraph are examples of this unconscious processing. In the same course, I learned how sleep is important in memory consolidation, and even diffuse learning can occur while sleeping. I find this amazing, and it caused me to read more about sleep.
Image by Sidnei Novais Magalhães Filho
Learning and memory are different but very related concepts. We study to learn, and we rely on our memory to later use this information. Memory has three main stages: encoding, consolidation, and retrieval. Tanisse wrote a great post about different study techniques, some of which we all used as study group partners. Of course, the studying stage is important in the encoding of memories. However, for the studying process to be completely effective, the consolidation and retrieval processes also need to work successfully. That is why I wanted to write about sleep for the next blog of our studying series.
A good night’s sleep has multiple cycles, consisting of different lengths of REM (rapid eye movement) and NREM (Non-rapid eye movement) stages. These stages have various lightness and different potentials to contain dreams or types of dreams.
Sleep has many health benefits, but I will focus only on its role in memory. Different sleep cycles and stages serve specific purposes (2). For example, REM sleep is important for memory consolidation and integration after learning; NREM sleep plays a role in clearing up memory for a better learning experience the following day (2–4). It is shown in many different studies that a good night’s sleep helps us learn better, even things like playing a musical instrument (5)! Having a good night's sleep both before and after studying will maximize what you learn.
Sleep is beneficial to our learning. Nevertheless, what about just ignoring those benefits and pulling an all-nighter anyway? Sleep deprivation can be chronic, like in insomnia, or acute, like when we study the whole night before an exam. Studies show that the impact of chronic and acute sleep deprivations can be different (6). There is one common theme, however: sleep deprivation does not only cause the lack of benefits we get from a good night’s sleep, but it causes negative health effects. Sleep deprivation can cause memory impairments, for example, or make us less attentive (6). Not things you would like to experience in an exam!
There are many sources about good sleep hygiene. To summarize the main principles from a recent study: Minimizing caffeine intake, especially later in the day, regular exercise routines, having a quiet sleeping environment, sticking to a regular sleep schedule, and minimizing stress are good practices to increase sleep quality (7). I also found a new study that focuses on improving sleep from a different aspect: How we value and cherish our sleep (8). Sleep is important, and we need to show that importance the way we do to other important aspects of our lives.
So, back to my question: How do you spend the night if you have an exam the next day? I hope you go for a good night’s sleep. As we have seen, proper sleep is important before learning as well. Let’s face it, as a student, that pretty much covers the whole term. The question should be for every night, not only the night before the exam. It is also shown that healthy habits, including regular exercise, a balanced diet, and proper sleep, are important in adolescents’ brain development (9). One night of sleep will not create miracles; not any more than one night of studying will. Maintaining good habits is crucial. Not needing to cram before an exam also requires a regular study schedule. Regular study and sleep schedules will also lower the stress level. It is a win-win-win!
I want to finish off my post with a fascinating story: Beginning of the 1900s, while there was still a discussion of whether the messaging between the neurons are chemical or electrical, Otto Loewi, an Austrian scientist, showed that it is chemical with a genius experimental setup (10). The reason why I am mentioning this in this post is that Loewi thought of this experimental design in his sleep (10). One night, he wakes up in the middle of the night from a dream with a great idea. He writes down some notes. However, the next morning, he could not make any sense of his notes. The following night, he has the same dream again—this time, instead of writing down some notes but goes directly to the lab to run the experiments. The result is the discovery of acetylcholine, which he named as ‘Vagustoff’ at that time. This discovery allowed him to get a Nobel prize!
Unfortunately, having a good night’s sleep is not enough to be a worldwide known scientist. Hard work is necessary. Regardless, it is important to give our sleep the importance it requires. As Dr. Espie says in his article, we have to “trust” our sleep (8). Our brain is a wonderful organ, and it continues to work 24 hours a day. Sleeping is not a loss of time. It is a treasure.
References:
1. Oakley B, Sejnowski T. Learning How to Learn: Powerful mental tools to help you master tough subjects [Internet]. Available from: https://www.coursera.org/learn/learning-how-to-learn
2. Walker M. Why We Sleep: Unlocking the Power of Sleep and Dreams. Scribner; 2017.
3. Walker MP, Stickgold R. Sleep, memory, and plasticity. Annu Rev Psychol. 2006;57:139–66.
4. Walker MP, Stickgold R. Sleep-dependent learning and memory consolidation. Neuron. 2004;44(1):121–33.
5. Simmons AL. Distributed practice and procedural memory consolidation in musicians’ skill learning. J Res Music Educ. 2012;59(4):357–68.
6. Krause AJ, Simon E Ben, Mander BA, Greer SM, Saletin JM, Goldstein-Piekarski AN, et al. The sleep-deprived human brain. Nat Rev Neurosci [Internet]. 2017;18(7):404–18. Available from: http://dx.doi.org/10.1038/nrn.2017.55
7. Irish LA, Kline CE, Gunn HE, Buysse DJ, Hall MH. The role of sleep hygiene in promoting public health: A review of empirical evidence. Sleep Med Rev [Internet]. 2015;22:23–36. Available from: http://dx.doi.org/10.1016/j.smrv.2014.10.001
8. Espie CA. The ‘5 principles’ of good sleep health. J Sleep Res. 2021;(September):1–7.
9. Ekman R, Fletcher A, Giota J, Erikson A, Thomas B, Bååthe F. A Flourishing Brain in the 21st Century: A Scoping Review of the Impact of Developing Good Habits for Mind, Brain, Well-Being, and Learning. Mind, Brain, Educ. 2021;1–11.
10. McCoy AN, Tan SY on. Otto Loewi (1873-1961): Dreamer and Nobel laureate. Singapore Med J. 2014;55(1):3–4.
Blog by Emine Topcu