Sleepy school kids (and sleepy surgeons)

Music: Thelonious Monk; Lana del Ray

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Sleepy kids in school

Adolescents undergo a natural, developmental, change in sleep patterns - they go to bed later, and wake up later. And, often, they are expected to wake up at the same time, or even earlier, for school, or for early morning sports. They may also have substantial commutes to school if they transition to a larger, more centralised, secondary school from a smaller, more local, primary school: a study of school commuting times in New York, for example, concluded that ‘average commuting time to school on foot or by public transportation increases from 10.3 minutes in kindergarten to 17.4 minutes in sixth grade and 31.3 minutes in ninth grade.

How you commute matters, too: one study suggests that ‘walking to and from school contributed 23% and 36% of MVPA’ per week-day (moderate-vigorous intensity physical activity). More walking would generally be a good thing, imho…

Does school start-time impact on academic performance? Early starts might imply less sleep, and later starts, more sleep (assuming that adolescents go to bed later, irrespective of start times). Studies on school start times are difficult to conduct - it’s difficult (for all sorts of practical and ethical reasons) to randomly allocate adolescents to differing school start times. We do know that persistent sleep restriction is generally bad for every aspect of cognitive, affective and psychomotor functioning.

Sleepy Surgeons

That last study on psychomotor functioning is worrying: it is one of many showing deterioration in functioning resulting from sleep deprivation - in this case, in orthopedic surgeons who have had just four hours sleep. The authors conclude that ‘Orthopaedic trauma surgeons showed deterioration in performance on a validated cognitive task when they had slept four hours or less the previous night’. They do not test outcomes in surgical theatres, but we can imagine that a sleepy surgeon might not perform as well as a well-rested surgeon (although, to be completely fair, this well-powered study or surgical performance suggests that we need not worry too much, but see here for a full review).

Start School Later

New evidence, using students who self-selected into early and late starts to school, shows an association between school start time and sleep duration, sustained attention, and academic performance: Italian students self-separated into earlier (8 a.m.) or later (9 a.m.) lesson starting times. The overall findings shouldn’t come as a surprise: both groups went to bed at about the same time, but the earlier start group had to get up an hour earlier - demonstrating that early rising doesn’t reset your underlying circadian rhythm.

Moreover, the authors found that ‘a one-hour delay in school start time is associated with longer sleep, better diurnal sustained attention, attendance, and improved academic performance. Notably, sleep changes were limited to school days. A delay in school start time should be seriously considered to improve sleep and academic achievements of students.

As I noted above, studies of this type are difficult to conduct ‘in the wild’, but the findings of this study cohere with a large body of evidence showing that sleep restriction is very bad for you (but you knew that anyway!).


Others have concluded similarly and perhaps even more dramatically: while ‘changes in sleep across adolescence are a normal part of development, many adolescents are getting insufficient sleep and are consequently, less likely to perform well at school, more likely to develop mood-related disturbances, be obese, and are at greater risk for traffic accidents, alcohol and drug abuse.’ The Centers for Disease Control (USA) have issued similar warnings, noting that ‘starting school later can help adolescents get enough sleep and improve their health, academic performance, and quality of life’.

One early pandemic-related finding on sleep in adolescents is particularly interesting, however: the pandemic has closed many schools, and adolescents are instead schooling at home. This means no transit time to schools. And the results, in a US sample, show that the ‘“natural experiment” caused by the shutdown of schools due to the COVID-19 pandemic led to a 2-h shift in the sleep of typically developing adolescents, longer sleep duration, improved sleep quality, and less daytime sleepiness compared to those experienced under the regular school-time schedule.’


Will our post-pandemic world take heed, and start school later? I doubt it: old habits die hard, and the habits of older people, die harder still.

However, all might not be bad on this front. A recent study by Sudha Raman and Andrew Coogan at Maynooth University found that a large number of us (42% in this sample) have abandoned the alarm clock. The authors write that:

…people working from home went to bed 48 minutes later and woke up almost an hour later on work days. The proportion of us who used an alarm clock to wake up in the morning on a work day dropped from 80% before restrictions to only 38% during restrictions.

The study is here.

As I noted here previously looking at the relationship between sleep and memory - we all should get regular, good quality, sleep: it’s one of the very best things you can do to promote and sustain health of brain and body. Furthermore, shun those fools who pretend they get by on a few hours sleep per night. There are lots of real-world examples, and they are generally not nice people.

And don’t get into a car with them…

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