Sensory regulation: the calm state of arousal and what knocks your child out of it

When I asked Jacqui, founder of Kids in Sync and a specialist in sensory integration, why my daughter falls apart in busy environments, she reached for an analogy.

"Think of it like a radio frequency," she said. "If you're tuned into Heart FM and you drift slightly above or below that bandwidth, you can't hear the music. The calm state of arousal is that bandwidth. When you're in it, you can attend, focus, listen, participate. When you drift out of it, everything gets harder."

That calm state of arousal is the sweet spot where your child's brain can function well. Their nervous system is constantly trying to get them there and keep them there. The problem is that for many autistic and neurodivergent children, the bandwidth is narrower, the drifting happens more easily, and getting back is harder.

What is sensory regulation?

Sensory regulation is your brain's ability to manage all the sensory information coming at it and maintain a comfortable level of alertness. Not too high (overwhelmed, anxious, fight-or-flight). Not too low (sluggish, zoned out, unreachable). Somewhere in the middle where you can get on with your day.

Right now, as you read this, your brain is doing it. You're filtering out:

• The feel of your clothes on your skin
• Background sounds in the room
• The brightness of your screen
• The pressure of the chair underneath you
• Whether you're slightly hungry or need the loo

You're not thinking about any of that because your brain is handling it automatically. It's keeping you in the bandwidth.

For many children, that automatic filtering doesn't work reliably. Some signals come through too loud. Others don't come through at all. And the brain has to work much harder to stay regulated, which leaves less capacity for everything else: learning, socialising, coping with change, managing emotions.

What knocks a child out of sensory regulation

Jacqui explained that the problem comes when a child is over-registering in some sensory systems or under-registering in others.

Over-registering (too much signal)

The child's nervous system reacts strongly to ordinary input. It doesn't take much to tip them into a heightened state of arousal.

Sound is one of the most common triggers. A busy, echoing lunch hall with clattering cutlery and children shouting. A public swimming pool. A classroom where 29 children are all making noise at once. "You can't concentrate," Jacqui said. "Your brain is just hearing all the noises around it and being irritated by that."

Touch is the other big one. If the tactile system is sensitive, being in a line of people where someone might brush past or suddenly touch you is genuinely alerting to the nervous system. Assembly, PE, playground games, crowded corridors: all potential triggers.

Other common over-registration triggers:

• Flickering fluorescent lights
• Strong smells (lunch hall, cleaning products, other children's food)
• Unexpected changes to routine
• Busy visual environments (cluttered displays, crowded rooms)
• Clothing textures (labels, seams, waistbands, socks)

Under-registering (not enough signal)

The child's nervous system doesn't pick up enough information. They seem zoned out, sluggish, or "in their own world." They might not respond to their name, not notice they're hungry or cold, or seem to have a high pain tolerance.

Under-registration is harder to spot because it doesn't cause visible distress. But it means the child isn't getting the input they need to reach the calm zone; they're stuck below it.

The confusing bit: a child can be both

This is what catches most parents out. A child can be over-sensitive to sound but under-sensitive to proprioceptive input. They can be overwhelmed by light touch but actively seek deep pressure. They can be distressed by a hand dryer and completely unbothered by a grazed knee.

"You can actually be alerted in some tactile situations but seeking other tactile input," Jacqui explained. "You like the feel of certain things on your skin, but you can't tolerate labels in your clothing or seams in your socks."

It's not contradictory. It's different parts of the same system calibrated differently.

Sensory seeking behaviour: self-regulation, not misbehaviour

This is the bit that changed how I think about my daughter's behaviour.

Jacqui demonstrated something simple. "Run your finger very lightly over the hairs on the back of your forearm," she said. I did. The sensation was surprisingly intense even though I was barely touching the skin. "Now grasp your wrist with your other hand and squeeze."

Instant relief.

"That squeeze is proprioceptive input," she explained. "It's hard input through the muscles and joints, and it's calming to the central nervous system."

That one demonstration explained a list of behaviours I see every day:

• Seeking hugs and wanting to be held tightly
• Hanging off monkey bars, climbing frames, door frames
• Pushing and pulling things, leaning against furniture
• Squeezing into tight spaces (under cushions, behind sofas)
• Wanting to hold your hand tightly, not loosely
• Chewing on things: sleeves, pencils, fingernails, shirt collars

That last one surprised me. Your jaw muscles are the strongest muscles in your body. Chewing or biting down on things is a child getting proprioceptive input into their system to calm down. They're self-regulating. The child chewing their sleeve in class isn't being naughty; their nervous system is trying to get back into the calm zone.

Sensory regulation through the school day

Once you understand the bandwidth concept, you can map it onto your child's daily experience. A typical school day starts to make sense differently.

Morning. The child wakes up. Arousal level is low (sleep is the lowest arousal state). They need to come up into the calm zone. If they're under-registering, they might be sluggish, hard to get moving, resistant to getting dressed. If clothing is a sensory issue, the day starts with a fight before they've even left the house.

School run. Noise, crowds, unpredictable movement. If the child is over-registering in auditory or tactile systems, they're already drifting above the bandwidth before they've reached the classroom.

Classroom. Flickering lights, background noise, the feel of the chair, the proximity of other children. The child's brain is working to filter all of this. If they're managing, they can learn. If they're not, they're spending all their processing power on staying regulated and have nothing left for phonics.

Lunch hall. Clattering cutlery, shouting, smells, crowding, queues, unpredictable touch. For many autistic children this is the hardest part of the day. "This is why I moved Annabel to a different school," I told Jacqui. "Frankly, because a class of 32 was too much." She nodded. "You're putting the science around her experience."

Afternoon. If the child lost regulation at lunch, they're not coming back for the afternoon. They're either in a heightened state (fidgeting, distressed, reactive) or a shutdown state (withdrawn, unreachable, appearing to daydream).

Home time. The child has been holding it together all day. The after-school meltdown isn't about what happened at 3:15pm. It's the entire day's sensory load finally releasing in the one place they feel safe enough to let go.

Sensory regulation and anxiety in autism

Jacqui was clear about the connection. "This is the bit that will be causing the anxiety," she said. "Because it's about arousal levels. If you can't maintain the calm state, anxiety builds."

The chain works like this:

• Sensory input pushes the child above the calm zone
• Their brain interprets the heightened arousal as threat
• Anxiety increases
• Anxiety makes sensory systems more sensitive (you notice and react to more when you're on high alert)
• More sensory input pushes them further above the calm zone
• The loop tightens

This is why environmental adjustments aren't a nice-to-have. They're an anxiety intervention. Reducing the sensory load in the classroom, the lunch hall, and the school run isn't about making the child comfortable; it's about keeping them in the bandwidth where anxiety doesn't escalate.

Sensory regulation strategies: getting back into the calm zone

Proprioceptive input (calming)

Deep pressure and heavy work through muscles and joints. This is almost always calming and is the foundation of most sensory diets.

• Bear hugs and firm squeezes
• Carrying heavy things (bags, books, shopping)
• Pushing against walls, pulling doors
• Climbing and hanging
• Chewing (crunchy foods, chew toys)
• Weighted blankets or lap pads
• Crawling, jumping on a trampoline

Reducing alerting input

• Noise-cancelling headphones in loud environments
• Removing clothing labels, switching to seamless socks
• Seat away from the door, window, or strip lighting
• Advance warning of loud events (assemblies, fire drills)
• A quiet space to decompress before re-entering

Sensory circuits

Jacqui described a specific sequence used in clinics and schools: start with an alerting activity (something that wakes the system up), move to an organising activity (something that requires coordination), finish with a calming activity (proprioceptive, deep pressure). The sequence matters. "You'd never end with an alerting activity," she said. "You start with alerting, then organising, then calming. You're doing a cycle that boosts arousal and then gradually returns it to a calm state."

For practical sensory strategies, see sensory diets for children. For what SI therapy involves, see what sensory integration therapy looks like.

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Don't know where to start? Jacqui offers a one-off parent consultation for £55 where you can talk through your child's difficulties and get advice on what to do next. Book a parent consultation at Kids in Sync →

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Jacqui is the founder of Kids in Sync, an award-winning children's therapy centre specialising in sensory integration, with clinics in Borehamwood and Twickenham. She is quoted throughout with her permission. This article combines what Jacqui explained to me with independent research; the research summaries are my own.

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Neuroequipped provides research-grounded information for parents and educators. It is not medical advice. If you have concerns about your child, speak to your GP or paediatrician.