Attention and circadian rhythms — how they groove together

16 Jun 20213-minute read
Attention and circadian rhythms

We all know the importance of a good night’s sleep, whether we’re a child or an adult. We feel refreshed, clear-headed and ready to make the most of a new day, rather than grumpy, emotional and distracted. Furthermore, many important physiological processes going on inside us rely on proper sleep – from metabolising our food to a multitude of hormonal processes.

The term ‘circadian rhythms’ may sound like a type of music but actually refers to internal processes that are instrumental in us getting a quality night’s sleep. Understanding circadian rhythms can mean understanding more about ourselves and, when it comes to kids, knowing when and how to expect certain levels of performance from them across the course of any given day.


What are circadian rhythms?

Think of circadian rhythms as your body’s internal 24-hour clock, running behind the scenes to control a number of important processes that our bodies need to perform on a daily basis.

As the Sleep Health Foundation explains, “Even if we don’t know what time it is, we still do things in cycles that go for about 24 hours. We sleep for part of every 24 hours and our body temperature rises and falls with a cycle length of about 24 hours. We have hormones and other systems in our body that go through this daily cycle as well. Exactly the same pattern is seen in almost every living thing on the planet.”

Given the foundational function circadian rhythms play in sleep, it’s not surprising that research has uncovered a profound link between these cycles and diverse aspects of physical and mental health.


Circadian rhythms and attention

As well as attuning our bodies to a night/day cycle, circadian rhythms influence a person’s energy levels at different points across their everyday routine. These energy levels impact cognitive processes and, in turn, our attention levels.1

Most kids tend to be more switched on across the afternoon while, at night and in the early hours of the morning attention, cognitive function ebbs to the lower end of the scale.1

With this in mind, it’s perhaps unsurprising that circadian rhythms can have an impact on how children function at school. Indeed, a number of studies have shown a strong link between a child’s daily schedule, the quality and amount of sleep they get each night, and their ability to develop the attention skills necessary to succeed in the classroom and in the wider world as they grow older.1

These findings have some important implications for children who might be having trouble keeping up with their classmates, or who are performing badly in tests.

Putting circadian rhythms to the test

In an article for The Conversation, Francesca Gino cited a study of the full population of around two million Danish public school students that evidenced the link between circadian rhythms reflecting through the time of day and their direct effect on performance in class and exams.

She observes, “As the day wears on, students (as we all do) become increasingly fatigued… ‘Cognitive fatigue’ (i.e. when the brain has to work harder to concentrate on tasks) can lead students to perform worse on tests taken later in the day and that breaks can recharge students’ energy.”

This means, in assessing whether a child may have an attention or learning vulnerability, the time of day that the assessment takes place could have a significant impact on the accuracy of the outcome. Similarly, if the child has been tasked with having to concentrate across a long period of time (without sufficient breaks to eat, relax and play), the outcomes of any assessment could be skewed.

When conducting assessments or tests with children on a regular basis, it is advised to conduct the test at the same time of the day, every time, to create a barometer from which the child’s performance can then be measured. If the time is varied, the results are also likely to vary depending on the child’s circadian rhythm. Additionally, conducting the test when the child is sufficiently rested – or, at the very least, when their energy levels have been recharged – is the best practice for performing tests or assessments.

In conclusion

Understanding when children’s attention levels are generally at their best – let alone the circadian rhythms of any individual child – may help with a better standardised result when administering tests, not to mention assist in identifying whether a child’s performance is underpinned by a disorder or by a lack of or disturbed sleep that is manifesting in cognitive issues.

It’s important to note that problems with sleep could suggest there’s a separate health issue that needs addressing – like sleep apnoea, for example – before arriving at a diagnosis of ADHD, autism (ASD) or any other attention-related vulnerabilities.

For the parents of children with an acknowledged issue, understanding the relationship between circadian rhythms and their impact on attention levels is important. Taking steps to help a child with quality rest will aid them in getting through the day and their brain will be given the best possible chance to process the millions of different things coming its way.  

For any standardised assessment, including TALi DETECT, the time when the test is taken can affect a child’s performance and the outcomes of this assessment. Ask us for details at


1. Valdez, Pablo. ‘Circadian Rhythms in Attention.’ The Yale journal of biology and medicine vol. 92,1 81-92. 25 Mar. 2019.