Arousal is all about alertness

Arousal at its simplest is how awake or alert or how tired you are.  It supports attention and focus.  There are a number of things which impact our level of arousal.  This includes how well we have slept, previous experiences and sensory inputs from the environment as well as our bodies.  In this article I will explore

  • What arousal is

  • Optimal arousal

  • Sensory inputs that might impact arousal

Key takeaways: Understanding arousal and alertness

1. Arousal refers to a child’s level of alertness—ranging from sleepy to overstimulated—and it fluctuates naturally throughout the day. Optimal arousal, or being “just right,” helps children focus, learn, and participate effectively in different settings.

2. Many factors influence arousal, including sleep, body sensations (like hunger or illness), stress, environment, and past experiences. Teachers and parents can support children by identifying the triggers and making adjustments, sensory strategies can sometimes help with this.

3. Sensory processing can impact arousal levels. Sensations from all senses can increase or decrease arousal levels. When there is sensitivity to sensory input this can cause overwhelm. If there are slower responses, children may appear passive or constantly seek stimulation. Sensory processing differences can make it harder for some children to their arousal in classroom settings. The impact sensory differences on arousal and how to support this is explored in GriffinOTs sensory processing awareness training.

boy with jacket hood over head laughing text what is arousal
boy with jacket hood over head laughing text what is arousal

Arousal is all about alertness

Arousal at its simplest is how awake or alert or how tired you are.  It supports attention and focus.  There are a number of things which impact our level of arousal.  This includes how well we have slept, previous experiences and sensory inputs from the environment as well as our bodies.  In this article I will explore

  • What arousal is

  • Optimal arousal

  • Sensory inputs that might impact arousal

Key takeaways: Understanding arousal and alertness

1. Arousal refers to a child’s level of alertness—ranging from sleepy to overstimulated—and it fluctuates naturally throughout the day. Optimal arousal, or being “just right,” helps children focus, learn, and participate effectively in different settings.

2. Many factors influence arousal, including sleep, body sensations (like hunger or illness), stress, environment, and past experiences. Teachers and parents can support children by identifying the triggers and making adjustments, sensory strategies can sometimes help with this.

3. Sensory processing can impact arousal levels. Sensations from all senses can increase or decrease arousal levels. When there is sensitivity to sensory input this can cause overwhelm. If there are slower responses, children may appear passive or constantly seek stimulation. Sensory processing differences can make it harder for some children to their arousal in classroom settings. The impact sensory differences on arousal and how to support this is explored in GriffinOTs sensory processing awareness training.

What is arousal?

The term arousal relates to how awake or alert or how tired you are.  Across a typical day it is very normal for alertness to fluctuate.  Students, and teachers, need to constantly adjust their levels of alertness throughout day and matching their arousal to the task and environment.

As a simplification, it can be helpful to think of arousal like steps, or a ladder.  At the bottom there is sleep.  At the top there is highly alert, agitated and stressed.  Somewhere in the middle there is alert and wakeful.  When alertness is too high or low, it is more difficult for individuals to access learning or to be successful at work.  Different activities also require different levels of arousal,. For example, arousal might be higher when playing a winning game of football compared to when writing an English essay. 

An important thing to remember is that arousal is controlled by our nervous system. Or body is constantly working in the background to keep us safe and to help us stay alive. It automatically increases arousal if we are in danger and decreases arousal when we are safe. For individuals with sensory processing needs, safe sensations (for example the school bell) can sometimes be perceived as a danger, so their body increases their arousal. I explore this is much more depth in section two of my sensory training which is included in the GriffinOT membership.

Image showing stair case with stressed at the top, deep sleep at the bottom and optimal in the middle. Steps are red at the bottom, green in the middle, yellow then red at the top.

Please note if you are using this image in any of your work (e.g. presentations, handouts) the correct citation is: Griffin, K. (2026). Arousal, Attention and Sensory Processing What’s the Links? GriffinOT. https://www.griffinot.com/arousal-attention-sensory-processing-adhd-autism/. This citation, including an active link must appear in your work both on the image page and in the reference list.

Matching arousal with the environment and task

When considering arousal, it is important to note that there is no perfect level of arousal for every situation.  As I mentioned above, different activities will invoke different states of alertness.  In some environments, for example a library or cinema, it is expected that you would be quiet.  However, in other environments, for example a sporting match or playground, it is expected that you would be much louder and engaged.  Each environment has its own expectations and demands.

Tasks also require different levels of alertness  If you’re trying to get a baby to sleep, you will lower your level of arousal to help them sleep.  You might sing a lullaby but you typically wouldn’t start blaring loud music at them.  When playing a game of football, alertness levels need to be much higher to stay focussed and to keep up with the speed of the game.

Throughout the day, week and month every individual needs to adjust their level of arousal to match the environment and task.  This adjusting is sometimes called regulation.  Some individuals, particularly those with sensory differences, find this harder to do than others.  They may need more support to reach optimal arousal.

Diagram by GriffinOT (copyright Kim Griffin) showing factors that impact sensory needs - venn diagram in the middle representing the child's needs (current state, motivations, foundations) and triangle outside with environment, task and relationships represented

Please note if you are using this image in any of your work (e.g. presentations, handouts) the correct citation is: Griffin, K. (2026). Arousal, Attention and Sensory Processing What’s the Links? GriffinOT. https://www.griffinot.com/arousal-attention-sensory-processing-adhd-autism/. This citation, including an active link must appear in your work both on the image page and in the reference list.

child holding a pen and looking up towards teacher
child holding a pen and looking up towards teacher

Optimal arousal

Optimal arousal the level of arousal which matches the environment and activity.  Sometimes it’s called ‘Just Right.’  There is no one exact ‘optimal’ arousal state that is correct for every situation. At night time, optimal arousal is a low energy state which facilitates sleep.  At school, optimal arousal is a focused energy state which allows the learner to attend and participate.  In the playground or at a party, it’s normal for optimal could be a higher energy state, as there’s more movement and usually excitement.

Additionally, all arousal states are appropriate at different times. For example, if you are stressed because of a upcoming deadline higher arousal might be expected. Or, if you were tired because you didn’t sleep well, it’s completely appropriate for you to feel tired.  It is important to help children to understand these differences, rather than to just expect them to be in the green zone all the time.

Arousal and sensory processing

Students with sensory processing differences usually have more difficulty organising, or regulating, their level of alertness.

Sensitivity (Over-Responsivity)

For students who are more sensitive to sensations, sensory inputs from the classroom typically increase their arousal.  This could include everyday sensations like the school bell, students singing in assembly, or the feeling of glue on their fingers when sticking a sheet in their book.  These students can also become quickly overwhelmed or overloaded by multiple sensory inputs occurring at the same time or a single one that is continuous.  This can result in behaviours like running away, refusing, avoiding, shutting down or having a meltdown.

Sometimes these students might seek out a different sensations to help them self-regulate.   For example, they may make noise to drown out other noises in the environment.  Or, they might chew, or seek proprioceptive sensory input to help to calm down. This would historically be called sensory seeking. It is important to be aware that sensory seeking is not always as straight forward as it looks, something that I explore in further depth in my online sensory success course.

Slower Responses (Under-Responsivity)

Students who are slower to process sensory inputs from their environment may be more passive.  Their arousal level may be too low for the task at hand. Sometimes, they need additional time to register sensory inputs or for the sensation to be at greater intensity before they notice it.  Unfortunately, if these  students are quiet and passive, they do not cause disruption and can be missed in the classroom.  It is really important to look out for them, as they will also be less engaged with their learning.

The other behaviour you may see in children with lower levels of arousals is sensory seeking.  These children are seeking out extra sensation to try to increase their arousal arousal.  They might move about, or make noise, or touch things and fidget.  These students are typically identified quickly and offered extra supports. Historically, these students might have been expected to sit still. This is not always the best option for them, as they have to divert their attention to sitting still, at the expense of listening to what the teacher is saying!

I explore how to differentiate between these two states in GriffinOT’s Sensory Aware training – this is included in GriffinOT’s membership.

Jasper’s story

Jasper has some sensitivity to noise.  This makes it harder for him to attend in class.  Some sounds, like the lunch bell and the door slamming, make him startle.  This increases his arousal and it takes him longer to calm down and refocus.

Some strategies that his teachers use to help to support him are headphones, a quieter space for lunch time and heavy work.

What impacts a person’s level of arousal?

There are a number of things that impact our level of alertness.

Body Sensations

This includes hunger, illness and pain.  It is much harder to attend and stay focus if you are hungry.  It is equally as hard to focus if you have a headache.  These are usually grouped together under the heading of interoception.

Sleep

Levels of sleep also impact arousal.  When tired, arousal is often lower.  However, it can also become increased due to stress when tired as well.

Current Stressors

Existing stressors will also impact level of arousal.  If an individual is worried about an exam, or a parent is nursing a sick child, their arousal level will likely be higher.

Cumulative sensations

It’s important to remember is that arousal builds up over time.  This means that a sensitive individual might be able to manage a sensory input for short periods but over time their arousal will increase.  Some individuals might be able to manage and hold themselves together in one situation, such as assembly, but this could lead to a meltdown or shutdown afterwards if they have not been given time and space to decrease their arousal.  For individuals who are slower to process sensory inputs, it means that their arousal might take longer to increase compared to their peers.

Environmental Expectations

Each environment has an unwritten expected level of arousal.  Compare a library, sporting stadium, staff meeting, church, music concert and theatre show there are ‘expected’ arousal levels foe each.

Sensory Inputs

Each environment also has its own sensory inputs. These will impact an individual’s arousal.  Some people may find a sporting stadium too overwhelming, whereas others might love the energy and noise.

The Task

Next, the task or activity impacts arousal.  If it is a task the individual finds easy or one they are very familiar with, they will likely remain calm.  However, if it’s a more difficult or unfamiliar task arousal might increase.  A perfect example of this is exam time.  For some students, the exam conditions increases their stress level, or arousal, and this affects their performance.

Trauma

A final thing to consider is any trauma experiences the individual may have had.  Trauma wires the brain in a different way.  This means that individuals might be hyper alert to potential threats.  Or, they may be used to shutting down in order to protect themselves.  If there is a history of trauma it is recommended that advice is sought from trained professionals.

There are many things that impact on arousal.  Some might be obvious, like a loud sound.  However, some might not be something you can immediately observe.  Such as the child has not slept well or they are worried about a family member who is ill.

Discussing arousal and self-regulation in further depth

You can listen to me explore these concepts in further depth with Dale on the SENDcast here:

How to support optimal arousal

Supporting arousal will look different for each individual. Individuals with higher arousal will need sensory strategies to help to decrease their level of alertness.  Those who are slower to respond typically need more sensations to increase their arousal.  Children and adults need to contiually adjust their arousal level across the day in order to focus, attend and participate. There are many strategies that can be used to support this.  Sensory strategies are one option and I explore how to use them further in this post – Sensory regulation strategies – What are they?

If you are a teacher and would like specific ideas for the classroom, then this article will also be relevant Sensory Strategies and Supports for the Classroom.

I also also covers arousal and regulation in much further depth in my online training and my book Success with Sensory Supports.

Arousal quick fire questions

How does arousal relate to sensory processing?

When thinking about arousal in a sensory processing context, therapists are referring to the overall level of energy or alertness in the body. Sensations can increase or decrease the arousal and this is why therapists use them to help children to calm down or to increase their arousal. 

What is the ‘green zone’?

In schools the ‘green zone’ often refers to an optimal level of arousal that allows a child to access learning. It is often used within regulation programmes such as Zones of Regulation. 

How does arousal affect learning?

If arousal is too high or too low, it can be hard to focus. This is because the body is not well organised. When arousal is too high the brain is too stressed, if it’s too low the brain is often too tired or distracted. 

How does arousal affect behaviour?

Yes, arousal affects behaviour. When arousal is too high, it can trigger a fight, flight or freeze response. This can look like hitting out, screaming, running away or disassociating. If it’s too low, then the child will likely be disinterested, or too tired to concentrate.

What are sensory breaks and how do I use them at school?

Sensory breaks are short movement or calming breaks that help children to refocus for learning. They are sometimes called brain breaks, sensory circuits or sensory diets. Depending on the child’s needs, they might include yoga, breathing, dance, or movement. 

About the author

All articles on the GriffinOT website are written by children’s occupational therapist Kim Griffin. Kim has over 25 years’ experience supporting children with sensory and skill needs, their teachers and families. She is the author of multiple books, presents all training at GriffinOT and hosts the EBPOT podcast. Kim is currently completing her PhD, focussing on supporting children’s self-regulation in schools, at Oxford Brookes University.

Date last updated by Kim: 9th April 2026

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