My learning curve
Before I studied sleep, my typical pre-exam preparation included re-writing my revision timetable 16 times (with progressively less ambitious productivity targets), eating a lot of chocolate biscuits, drinking a lot of coffee, and staying up late in a mad panic as I read and re-read the same material.. over, and over, and over again.
This approach, though unpleasant, always resulted in at least a pass mark, so I never really thought of changing it. Of course, there were a few downsides:
- revision was fraught with stress and anxiety, and at the end of any exam period, I was hit by a wave of fatigue;
- I always seemed to contract a nasty cold, which put a bit of a damper on the post-exam festivities;
- even when I passed an exam, I noticed that a few months later, if the same material was tested, my recall was very poor, which resulted in extra revision time.
Now that I am much older, and a little wiser, I realise that my sleep-neglect strategy was counterproductive...
1. Sleep allows us to concentrate, and think faster
If I had protected time for sleep, I would have been able to focus more effectively. If you sleep for less than the recommended 7+ hours for adults, or 8-10 hours for teenagers, you build up a sleep debt. With every night of short sleep, lapses in attention increase... just 10 nights with 6 hours sleep has a similar effect on your reaction time as 24 hours without sleep; you respond similarly to someone with a blood alcohol concentration over the drunk driving limit.
2. Sleep consolidates important memories
During sleep, new memories are strengthened, and reinforced. The brain prioritises memories which have strong emotional meaning, or that are associated with rewards. In other words, you’re less likely to remember things that you think are boring! Replaying experiences during REM sleep may be one of the ways that we strengthen the electrical memory signatures.
3. Sleep helps us to forget, so that we can learn again tomorrow
New memories are initially stored in the hippocampus, the brain’s centre of working memory. The hippocampus only has limited storage capacity. Neurons communicate via connections called synapses. During sleep, a process of ‘synaptic pruning’ or re-setting takes place, as we crop the connections which are less important, and strengthen those which are important. This frees up more capacity to learn the next day. Studies in mice have found that the brain’s synapses shrink by up to 20% during sleep.
4. Sleep eases worry
One of the most important functions of sleep during exam season is to rebalance emotions. If you deliberately compress your sleep, your brain is more likely to go into ‘fight or flight’ mode. You will stay on high alert, making it harder to get a restful night’s sleep. Sleep loss makes you feel even more anxious and stressed. This can fuel a cycle of over-working and lack of sleep, since you constantly worry that you’re not doing enough…
Cramming vs. napping
So, with all this in mind, is there a better way to revise than the mad cram-anxiety cycle?
In one study, volunteer students were taught about crabs and spiders for eighty minutes (Cousins et al. 2019). They were split into one of three groups for an hour: cramming (re-reading the presented material), a nap or a break (watching videos on YouTube). Teaching continued for a second eighty minute session. Students were tested at the end of the same day to see how much they could remember, and one week later.
It emerged that on the same day, both the napping and cramming group scored more highly than the group that had a break. One week later, only the napping group had retained more information than the group that rested - suggesting that a nap on the day of learning could help to consolidate memories, and free up more capacity to learn.
Tips for sleep during exam season
Build sleep into your schedule to avoid a sleep debt
Treat sleep like any other critical element of revision: plan in it! Teenagers need 8-10 hours and adults at least 7 hours to optimise learning and memory.
Take regular breaks
It takes energy to focus. We make fewer mistakes and concentrate more easily with regular breaks, at least every 2 hours, preferably more often. To help make the most of breaks, get the body moving and get some natural daylight to boost alertness.
Use caffeine strategically
Hopefully if you are making time for sleep, and taking breaks, you will be less reliant on caffeine… Caffeine is a stimulant, so if you’re stressed or anxious, it can amplify these feelings. Even caffeine consumed 6 hours before bedtime can interfere with the quality of your sleep, so use in moderation and try to avoid caffeinated hot drinks and soft drinks after 2pm.
Do you need a nap?
If you’re struggling to keep your eyes open, a short nap in the early afternoon can help to refresh alertness, mood, and your capacity for learning. If you nap for less than half an hour you should avoid sleep inertia, the groggy feeling when you wake up from deep sleep. Most people find it easiest to nap between 1 and 3pm. If you struggle to nap, a quiet period of rest can still reduce your stress levels and give you a more positive mindset for learning
Wind down before bed
During exam season it’s inevitable that you’ll have a lot on your mind. If your brain is busy all day, you may need a bit of extra time to wind down before you get into bed. Stop working at least 30 minutes before bed, but preferably at least an hour before bed. Do something relaxing which you enjoy, such as a bath, listening to music, or reading a book, before you climb into bed, and only get into bed when you’re feeling sleepy.