The Body That Thinks: Sensory Processing, Autonomic Dysregulation, and the Embodied Experience of Level 1 Autism Spectrum Disorder

Introduction

Autism Spectrum Disorder has traditionally been described in terms of observable behaviours, including social communication differences and restricted or repetitive patterns of activity. While these descriptions are clinically useful, they capture only part of the condition. Increasingly, research and lived experience indicate that ASD is also deeply embodied, involving sensory processing, interoception, and autonomic nervous system regulation.

This shift reflects a broader movement in neuroscience toward recognising the integration of brain and body in shaping cognition, emotion, and behaviour.

This paper presents a medical narrative grounded in lived experience, arguing that ASD is best understood not as a purely cognitive condition, but as an integrated mind–body system in which sensory input, physiological state, and cognitive processing are inseparable.

Sensory Amplification: Experiencing the World at Volume

The sensory environment is not experienced passively. For many individuals with ASD, it is amplified.

“Life hums louder… a rhythm I partake.”

This reflects sensory hyper-responsivity, where auditory, visual, tactile, or multisensory input is processed with increased intensity.

Common features include:

• Heightened sensitivity to sound

• Visual overstimulation

• Tactile discomfort

• Difficulty filtering competing inputs

This amplification alters baseline neurological state, increasing cognitive load and reducing tolerance for additional demands.

Interoception: The Internal Sensory Landscape

Beyond external stimuli lies the internal sensory world— interoception, the perception of physiological states such as heart rate, breathing, and internal tension.

Individuals with ASD may experience:

• Heightened interoceptive awareness

• Reduced clarity in interpreting bodily signals

• Strong coupling between physiological and emotional states

The lived narrative reflects this:

“My heart races… the body speaks before the mind can respond.”

This illustrates a key clinical insight: physiology may precede cognition. Emotional experience is often shaped by the interpretation of bodily signals already in motion.

Autonomic Dysregulation: The Misfiring System

The autonomic nervous system regulates fundamental physiological processes, including cardiovascular function, respiration, and stress response.

In ASD, this system may show patterns of dysregulation, including:

• Increased sympathetic activation

• Reduced parasympathetic recovery

• Greater variability in physiological response

The lived experience captures this instability:

“A delicate dance… regulation slipping beyond control.”

When autonomic regulation becomes unstable, the body may respond disproportionately to relatively minor triggers. Recovery may also be prolonged, resulting in extended periods of reduced functional capacity.

The Embodied Cascade Model

ASD can be conceptualised as an embodied cascade, in which events unfold sequentially across sensory, physiological, cognitive, and emotional domains.

Stage 1: Sensory Trigger

Environmental input initiates the sequence.

Stage 2: Sensory Amplification

Input intensity exceeds manageable thresholds.

Stage 3: Autonomic Activation

Physiological arousal increases (e.g., heart rate, breathing changes).

Stage 4: Interoceptive Overload

Internal bodily signals dominate awareness.

Stage 5: Cognitive Narrowing

Executive function reduces; flexibility declines.

Stage 6: Emotional Dysregulation

Emotional responses intensify rapidly.

Stage 7: Functional Shutdown or Overwhelm

“Living life in pieces… never quite the same.”

This cascade explains why responses may appear disproportionate. The visible behaviour reflects cumulative system activation rather than a single trigger.

Emotional Regulation as a Physiological Process

Emotional dysregulation in ASD is often body-mediated rather than purely cognitive. Physiological arousal:

• Precedes emotional awareness

• Shapes perception of events

• Limits access to regulation strategies

This explains why cognitive strategies alone may be insufficient during periods of high arousal.

Recovery: The Essential Phase

Recovery is a necessary phase of the regulatory cycle.

Following overload:

• Sensory input must be reduced

• Physiological state must stabilise

• Cognitive capacity must be restored

Recovery should be understood not as withdrawal, but as functional restoration.

Patient Voice

It is not just in my mind—it is in my body.

When something overwhelms me, it is not a thought I can change. It is a reaction I feel.

My heart changes.

My breathing changes.

My focus disappears.

By the time I realise what is happening, my body is already engaged.

Others see the reaction.

They do not see the build-up.

Managing my environment is not avoidance.

It is regulation.

Clinical Implications

Recognising ASD as Embodied

Assessment should include sensory, interoceptive, and physiological dimensions.

Integrating Physiological Interventions

Effective support includes breathing regulation, sensory modulation, and environmental control.

Moving Beyond Cognitive-Only Models

Interventions must integrate body and mind.

Early Identification of Cascade Stages

Recognising early signals allows prevention of full escalation.

Key Learning Points for Clinicians

• ASD is a whole-body condition

• Sensory amplification is central to experience

• Autonomic dysregulation drives many outcomes

• Emotional responses are often physiologically mediated

• Recovery is essential for function

• Integrated approaches are required

Conclusion

Level 1 Autism Spectrum Disorder cannot be fully understood without recognising its embodied nature.

The lived experience reveals a system in which:

• Sensation shapes physiology

• Physiology influences cognition

• Cognition directs behaviour

Understanding this integration allows for more accurate clinical insight and more effective support [1-15].

References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders. 5th ed. Washington (DC): American Psychiatric Association.
2. Robertson, C. E., & Baron-Cohen, S. (2017). Sensoryperception in autism. Nature reviews neuroscience, 18(11), 671-684.
3. Garfinkel, S. N., Seth, A. K., Barrett, A. B., Suzuki, K., & Critchley, H. D. (2015). Knowing your own heart: distinguishing interoceptive accuracy from interoceptive awareness. Biological psychology, 104, 65-74.
4. Benarroch, E. E. (1993). The autonomic nervous system.Neurology, 43, 1405-1409.
5. Raj, S. R. (2013). Postural tachycardia syndrome (POTS). Circulation, 127(23), 2336-2342.
6. Arnsten, A. F. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature reviews neuroscience, 10(6), 410-422.
7. Corbett, B. A., Simon, D. (2014). Emotion regulation in autism spectrum disorder. J Autism Dev Disord, 44(9), 2263-2273.
8. Porges, S. W. (2007). The polyvagal theory. Biol Psychol, 74, 116-143.
9. Craig, A. D. (2002). How do you feel? Interoception: the sense of the physiological condition of the body. Nature reviews neuroscience, 3(8), 655-666.
10. Marco, E. J., Hinkley, L. B., Hill, S. S., & Nagarajan,S. S. (2011). Sensory processing in autism: a review of neurophysiologic findings. Pediatric research, 69(8), 48-54.
11. Mazurek, M. O., Vasa, R. A., Kalb, L. G., Kanne, S. M.,Rosenberg, D., Keefer, A., ... & Lowery, L. A. (2013). Anxiety, sensory over-responsivity, and gastrointestinal problems in children with autism spectrum disorders. Journal of abnormal child psychology, 41(1), 165-176.
12. Shah, P., Hall, R., Catmur, C., Bird, G. (2016). Interoception and emotion in autism. J Autism Dev Disord, 46, 362–372.
13. Thayer, J. F., Lane, R. D. (2000). Neurovisceral integration.Biol Psychol, 54, 187–211.
14. Schaaf, R. C., Benevides, T. W., Mailloux, Z., et al. (2014). Sensory integration interventions. Am J Occup Ther, 68, 252-263.
15. Pellicano, E., & den Houting, J. (2022). Annual research review: Shifting from ‘normal science’ to neurodiversity in autism science. Journal of child psychology and psychiatry, 63(4), 381-396.