Why we sleep: want to ace that exam? Sleep!

What improves our memory, makes us more creative and healthier looking? Beyond any doubt; a good night’s sleep!

Shakespeare, in MacBeth Act 2, Scene 2, states that ‘Sleep is the chief nourisher in life’s feast’. He was right and clearly much ahead of his time.

Our sleep can be divided in roughly 4 parts, from stage 1 to 4, the last being the REM sleep stage. Each of these stages provide our body & brain with different things we need. We pass through each cycle multiple times during our sleep.

Stage 1, NREM, the transition phase, is basically going from being awake to falling asleep. This normally takes only a few minutes. Stage 2 NREM and 3 NREM take us gradually into deep, deep sleep. Sleep that occurs in stage 3 provides us with vital resources, allowing us to restore and regenerate our bodies; repair our tissue; regrow cells and strengthen our immune systems.

The last stage of sleep (stage 4) is the REM sleep and here is where a lot of essential brainwork happens. The brain is very active at this part of the sleep cycle and you may have vivid dreams. What happens during the REM sleep could be described as a way of emptying our metaphorical in-tray (meaning our short-term memory formed in the Hippocampus) and refiling and storing this information in our long-term memory. Our REM sleep allows the brain to clear out waste; to get rid of information overflow. It helps to solve problems, to solidify information and helps to recover from emotion upheaval. Sleep is the ultimate body and mind repair shop.

When, for example, you are cramming for an exam late at night and feel you can’t absorb any more information, the advice to ‘sleep on it’ is actually the best thing you can do. Because your ‘in-tray’ will be full and needs to be cleared. It is like clicking a ‘save’ button on what you have learned. Your brain will do the rest whilst you snooze. Not sleeping will impair this important part of our neuroscience.

Pulling an all-nighter? You may be starving your brain

Matthew Walker, a Professor of Neuroscience and Psychology at Berkeley University, conducted a study with a group of students who said they were doing ‘all-nighters’ to cram for an exam. His study divided the students into 2 groups. Both groups were asked to sleep in his lab under the supervision of well-trained psychologists and neuroscientists. The first group was a sleep group and the second a sleep deprivation group. The sleep deprivation group was kept awake all night. Students of both groups were tested around midday the following day and put inside an MRI scanner and were asked to learn a specific list of facts, one by one, whilst snapshots were taken of their brain activity.

Both groups were then asked to sleep two nights without interruption and the same MRI tests were performed two days later at the same time of the day. All participants were asked to recall the list of facts learned two days prior. These tests showed that the sleep deprived group had an unbelievable 40% learning deficit compared to the sleep group. This shows that the difference between acing an exam or failing it may indeed lie in whether you are sleeping enough the night before the exam.

A very good reason not to postpone studying to the very last moment. Sleep on it.

Recommended reading:




Matthew Walker. Why we Sleep. The New Science of sleep and dreams. Penguin Books. 2017