Understanding the Nervous System’s Response to Stress

Anxiety, Stress, and Burnout

By Hanada Kardassopoulos, RP, MACP, M.Ed. Registered Psychotherapist |  Founder, Live Your Life Therapy | Toronto and Virtual  |  Ontario-Wide

“I Know I Am Safe. So Why Does My Body React Like I Am Not?”

That question stopped me the first time a client said it aloud in session. Not because it was unusual, but because I had heard some version of it so many times before.

The meeting is not a threat. The email was not intended as a criticism. The disagreement does not mean the relationship is ending. Yet the heart races. Thoughts spiral. The body tenses before there has been any time to think.

If you have ever experienced this, you are not overreacting. You are not broken. Your nervous system is doing something far more sophisticated.

The Mind and the Nervous System Are Not the Same Thing

Most people assume that if they understand something intellectually, their body should follow. That if they know they are safe, they should feel safe. The mind and the nervous system, however, operate on entirely different timelines and through entirely different mechanisms.

The mind processes language, logic, and conscious thought. The nervous system processes pattern, history, and threat. It does not read a situation. It reads the signals a situation produces, compares them in milliseconds against everything it has ever learned, and responds accordingly.

This is why insight alone rarely changes a physiological response. You can know, with complete certainty, that you are safe in the present moment, and your nervous system can simultaneously register the same moment as a potential threat, because something about it resembles an experience from the past.

Your Nervous System Has One Job

Dr. Stephen Porges, whose polyvagal theory has reshaped our understanding of the autonomic nervous system, describes a process he calls neuroception: the nervous system’s automatic, unconscious scanning of the environment for cues of safety, danger, or life threat. It happens below the level of conscious awareness, faster than thought (Porges, 2022).

When neuroception detects a cue associated with past threat, the body responds. The sympathetic branch activates. Heart rate increases. Muscles brace. Attention narrows. This response requires no decision and does not ask for permission. By the time the thinking mind registers that something feels off, the body has already been responding for several seconds.

This is not a malfunction. It is the nervous system fulfilling its primary purpose.

What Your Nervous System Knows Is Shaped by What You Have Lived

The nervous system does not respond to the present moment in isolation. It responds to the present moment filtered through the accumulated weight of every significant experience that came before it.

For individuals who have lived with chronic stress, unpredictable relationships, sustained pressure to perform, or early experiences that felt threatening or overwhelming, the nervous system has often learned to stay closer to the edge of activation. Not because something is wrong with it, but because that vigilance was once necessary (Yaribeygi et al., 2017).

Research in interpersonal neurobiology demonstrates that early relational experiences shape the developing nervous system in ways that influence emotional and physiological responses throughout adult life. These patterns are not stored as explicit memories that can be recalled and reconsidered. They are encoded in the body itself, activated by cues that resemble the conditions in which they were first formed (Siegel, 2020).

The nervous system that tenses in a routine work meeting may have learned, years earlier, that scrutiny was dangerous. The body that braces during a minor disagreement may have learned that conflict carried consequences. These are not irrational responses. They are loyal ones.

From “What Is Wrong with Me?” to “What Did I Learn?”

One of the most significant shifts in therapy occurs when a client stops asking what is wrong with them and begins asking what their nervous system learned, and when, and why. Shame cannot survive curiosity, and curiosity is precisely what creates the conditions for something to change.

In my practice, this shift is supported through approaches that work at the level where the learning originally occurred. Somatic therapy works directly with breath, movement, posture, and bodily sensation as entry points into regulation that cognitive approaches alone cannot reach. Through repeated experiences of safety in the body, the nervous system gradually updates its understanding of what the present moment requires (Kuhfuss et al., 2021).

Internal Family Systems offers a framework for the protective parts that respond to perceived threat: the part that freezes, the part that over-explains, the part that scans a room before anyone has spoken. IFS does not ask clients to override these parts. It invites curiosity about what they are protecting and what they would need to trust that something has genuinely changed (Schwartz and Sweezy, 2020).

Compassionate Inquiry, developed by Dr. Gabor Maté, supports exploration of what originally shaped these patterns, approaching that history with care rather than judgment.

Lasting Change Lives in the Body

Therapy is not about convincing yourself to think differently. It is about helping your nervous system accumulate enough experiences of genuine safety that it no longer needs to respond to every challenge as though it were a threat. The nervous system that learned to protect you can also learn, over time, that protection is no longer the only option available.

Understanding why you respond the way you do is the first step. Helping your nervous system experience something genuinely different is where lasting change begins.

Ready to Understand Your Nervous System Rather Than Fight It?

If you recognize yourself in this, and you are ready to understand your nervous system’s responses rather than fight them, I invite you to book a free 15-minute consultation. I work with adults across Ontario who are ready to move from self-blame toward genuine self-understanding.

Book Your Free Consultation: lifeyourlifetherapy.janeapp.com

www.liveyourlifetherapy.com

Virtual sessions available across Ontario  |  No waitlist

References

Kuhfuss, M., Maldei, T., Hetmanek, A., & Baumann, N. (2021). Somatic experiencing: Effectiveness and key factors of a body-oriented trauma therapy: A scoping literature review. European Journal of Psychotraumatology, 12(1), Article 1929023. https://doi.org/10.1080/20008198.2021.1929023

Maté, G. (2022). The myth of normal: Trauma, illness and healing in a toxic culture. Knopf Canada.

Porges, S. W. (2022). Polyvagal theory: A science of safety. Frontiers in Integrative Neuroscience, 16, Article 871227. https://doi.org/10.3389/fnint.2022.871227

Schwartz, R. C., & Sweezy, M. (2020). Internal family systems therapy (2nd ed.). Guilford Press.

Siegel, D. J. (2020). The developing mind: How relationships and the brain interact to shape who we are (3rd ed.). Guilford Press.

Yaribeygi, H., Panahi, Y., Sahraei, H., Johnston, T. P., & Sahebkar, A. (2017). The impact of stress on body function: A review. EXCLI Journal, 16, 1057–1072. https://doi.org/10.17179/excli2017-480