By Al McConville, Director of Teaching and Innovation
The crucial role of sleep in learning and wellbeing has been much in the press recently. As scientists gradually understand more fully the underlying processes of memory and cognition, it is increasingly clear how central a good night’s sleep is to optimal functioning.
At a recent Friends of Bedales meeting, a group of staff and students presented the latest research on sleep and adolescence, and how it relates to our practice, now, and potentially in the future. What, for example, would the impact of a later start to the school day be…?
I produced a handout sharing some key messages harvested from several books: Matthew Walker’s Why We Sleep; Till Roenneberg’s Internal Time; Sarah-Jane Blakemore’s Inventing Ourselves: The Secret Life of the Teenage Brain; and Dan Pink’s When: The Scientific Secrets of Perfect Timing.
- Sleep is strongly correlated with success in laying down new memories and other elements of cognitive performance, including focus, understanding, speed of processing and problem-solving; age appropriate levels of sleep lead to better memory and optimal cognitive function overall.
- During the day we store information in our short-term memory bank, the hippocampus. It needs to be cleared out daily to make space for new memories; that clearing out, or transfer to long-term memory in the cortex, happens primarily at night. Short-term memory capacity is refreshed in proportion to the number of ‘spindles’ that occur during sleep.
- There is a strong biological setting in all individuals which dictates their natural waking/sleeping times – chronotypes. It’s not good for you to try and work against this; very little ‘entrainment’ (i.e. getting used to forced alternatives) is possible.
- Sleep deprivation is correlated strongly with the full spectrum of mental health issues.
- Even a relatively small but regular shortfall of the necessary sleep leads to sleep deprivation indicators.
- The most important sleep for strengthening memory and learning (REM sleep) tends to happen at the tail end of the cycle, when the sleep is most ‘spindle-rich’, which is also the bit that is most often cut short.
- Teenagers need nine hours’ sleep on average; 8-10 hours is the range. However, their chronotypes shift later by 1-3 hours during adolescence, so their natural bed/wake times shift later.
- There is evidence from America in particular that shifting the same start time of schools back leads to improved academic performance. Locally, Alton College (sixth form only) starts at 10am.
- Even with enough sleep, there are variations in the cycle as to when we’re most cognitively capable of doing different kinds of work: earlier in the cycle is better for analytical thinking, while later in the cycle is better for more creative, ‘diffuse’ work.
- There is a big slump in attentiveness in the early afternoon for most people, adequately slept or not. This is somewhat later for teenagers. We’re ‘bi-phasic’ – people who know when their ‘slump’ is can (ideally) plan less cognitively demanding activities for that period.
- Naps perform something of a corrective to sleep deprivation, though are only really a sticking plaster, since a full cycle is necessary to perform all the functions of sleep.
- Watch out for alcohol – for memories to be fully, reliably ‘laid down’ takes several days, or rather several sleeps, and alcohol can wipe out new neuronal growth three days after a new memory is formed. Nicotine also reduces the depth of sleep.