Nervous system dysregulation can shape how we think, feel, and respond—often without our awareness. When the body and brain become stuck in patterns of hyperarousal (e.g., anger, anxiety) or hypoarousal (e.g., shutdown), it can be challenging to stay present, communicate effectively, or manage everyday stress. At VMA Psych, we guide clients in understanding these physiological responses, recognizing their personal patterns, and developing strategies to restore a sense of safety and regulation.

This article explores the science of nervous system dysregulation, examining the Fight, Flight, Freeze, and Fawn responses, the Window of Tolerance, Emotional Flooding, and the Polyvagal Theory. We’ll also share practical grounding techniques to help you navigate moments of dysregulation and reconnect with a sense of centred calm and control.

What Is Nervous System Dysregulation?

Nervous system dysregulation occurs when the body’s autonomic nervous system (ANS) becomes stuck in survival mode due to prolonged stress, trauma, or chronic overwhelm. This results in physiological and emotional responses that are disproportionate to the current situation.

Rather than moving fluidly between states of activation and rest, individuals with a dysregulated nervous system may remain in heightened arousal (hypervigilance, anxiety, anger) or collapse into a state of shutdown (numbness, dissociation, depression). This makes it hard to “show up” in relationships, at work, or even for ourselves.

Trauma Responses: Fight, Flight, Freeze, and Fawn

Our nervous system is built to protect us. When we sense danger—whether real or perceived—it instinctively activates one of four trauma responses:

1. Fight

The fight response activates when the body prepares to confront a perceived threat. The sympathetic nervous system floods the body with adrenaline, noradrenaline, and cortisol, increasing heart rate, sharpening focus, and directing blood to the muscles for enhanced strength and speed.

Emotionally, this might show up as anger, irritability, or a need to control. These reactions can be protective in true danger, but when they become habitual, they may lead to conflict, defensiveness, or emotional exhaustion.

2. Flight

The flight response drives us to escape or avoid danger. The same stress hormones—adrenaline and cortisol—heighten alertness and create an urge to move, run, or “fix” things.

In this state, the amygdala stays on high alert while the prefrontal cortex (responsible for logic and reflection) quiets down. This can make it difficult to think clearly or slow down.

People in a state of flight often feel anxious, restless, or constantly busy—sometimes using movement or productivity to manage internal tension. Over time, stillness can even start to feel unsafe.

3. Freeze

When neither fighting nor fleeing feels possible, the nervous system may default to a state of freeze. This is governed by the dorsal vagal complex of the vagus nerve, which slows the body down to conserve energy and reduce pain.

Heart rate drops, muscles tense, and endorphins are released, creating a sense of numbness or disconnection. Many describe it as feeling “stuck,” foggy, or detached from their body.

This response often develops after chronic or inescapable trauma, when the brain learns that shutting down is the safest way to survive.

4. Fawn

The fawn response, a term popularized by therapist Pete Walker, involves seeking safety through appeasement. It’s the nervous system’s way of avoiding danger by keeping others calm or happy.

In this state, both the sympathetic (fight-or-flight) and parasympathetic systems are active—creating anxious energy paired with a drive to connect. The ventral vagal branch of the vagus nerve, a component of the social engagement system, prompts us to seek approval or maintain harmony.

This might look like people-pleasing, over-accommodating, or losing your sense of self to avoid conflict. The brain’s reward system can even release oxytocin and dopamine when others respond positively, reinforcing the pattern.

These responses are not conscious choices but automatic survival mechanisms encoded in the nervous system. Understanding them can help us respond to stress with awareness rather than judgment—and begin retraining the brain and body toward safety and regulation.

The Brain and Body in Dysregulation

When we feel unsafe, our brain and body automatically shift into a state of survival. This is controlled by the autonomic nervous system (ANS) and the limbic system, which work together to protect us from harm.

When dysregulated, the amygdala—the brain's fear centre—becomes overactive, scanning for threats. It signals the hypothalamus to activate the HPA axis (hypothalamic-pituitary-adrenal axis) and floods the body with stress hormones, such as cortisol and adrenaline. In true danger, these hormones sharpen focus and prepare the body for action.

At the same time, the prefrontal cortex—the part of the brain responsible for logic, reasoning, and emotional regulation—temporarily goes offline, allowing instinct to take over. With repeated stress or trauma, the nervous system can become “stuck” in these survival states, reacting to ordinary experiences as though they were dangerous. This is how chronic stress and unprocessed traumas often lead to fatigue, anxiety, inflammation, and difficulty regulating emotions. Over time, the brain and body can begin to mistake everyday stressors for emergencies, keeping the nervous system in a constant state of tension.

The Window of Tolerance: Understanding Your Emotional Bandwidth

The “Window of Tolerance,” a term coined by Dr. Dan Siegel, describes the optimal arousal zone where a person can function effectively and stay emotionally regulated. When within this window, we can:

• Respond to stress without becoming overwhelmed

• Stay present and grounded

• Reflect and make choices, rather than react impulsively

  
  

When we fall outside of this window:

• Hyperarousal leads to anxiety, panic, racing thoughts, or anger.

• Hypoarousal leads to shutdown, depression, numbness, or dissociation.

  
  

What Impacts Our Window of Tolerance?

Several factors can narrow or widen your window:

• Past Trauma: Especially unresolved or early childhood trauma

• Upbringing: Emotionally neglectful or chaotic environments can make regulation difficult

• Chronic Stress: Financial strain, caregiving burdens, or unsafe relationships

• Health: Illness, hormonal imbalance, or nervous system conditions

• Sleep and Nutrition: Poor rest or inconsistent meals can make regulation harder

• Neurodivergence: Individuals with ADHD or autism may naturally have narrower windows of tolerance

  
  

The good news? The window of tolerance can be expanded with the right tools, support, and education on the nervous system.

Emotional Flooding: When It Feels Like Too Much

Emotional flooding occurs when the nervous system exceeds its window of tolerance, becoming overwhelmed by intense emotion. In this state, the body reacts as if it’s under threat, even when the danger is emotional rather than physical.

During emotional flooding, people may:

• Struggle to process what’s being said

• Feel a rush of panic, anger, or helplessness

• Shut down, dissociate, or go blank

• Say or do things they later regret

  
  

Physiologically, heart rate increases, breathing becomes shallow, and the brain’s executive functions temporarily go offline. This makes it hard to think clearly, regulate emotions, or communicate effectively. Flooding is common in relationships—particularly during arguments—when one or both people become so overwhelmed that they struggle to stay engaged. It’s not a sign of weakness, but a protective response from the nervous system trying to keep us safe.

What Helps:

• Step away from the situation (with clear communication if possible)

• Use grounding techniques like deep breathing or cold water

• Come back when your system has settled

• Learn to recognize early signs so you can intervene before it escalates

  
  

Working with a therapist can help you identify your personal cues for flooding and build emotional regulation tools to restore safety in both your body and your relationships.

Polyvagal Theory: The Science of Safety and Connection

Developed by Dr. Stephen Porges, the Polyvagal Theory explains how our autonomic nervous system responds to safety, danger, and life-threatening situations. It highlights the role of the vagus nerve, which connects the brainstem to key organs, including the heart, lungs, and gut. While the Polyvagal Theory is still being studied, its framework offers a helpful way to understand how our body and mind respond to cues of safety and threat.

The theory outlines three primary states:

1. Ventral Vagal (Safety/Connection): Calm, grounded, and socially engaged. This “rest and digest” state supports healing, learning, and growth.

2. Sympathetic Activation (Fight or Flight): Mobilized for action. Useful in genuine danger but draining if chronically triggered.

3. Dorsal Vagal (Freeze/Shutdown): Immobilized, numb, or withdrawn. A protective response when escape feels impossible.
   

By recognizing our current state, we can choose strategies to shift toward safety and connection, promoting resilience and well-being.

The Vagus Nerve: A Key to Regulation

The vagus nerve is the longest cranial nerve and a central player in the parasympathetic nervous system. It helps regulate heart rate, digestion, emotional regulation, and even vocal tone. When the vagus nerve is toned and functioning well, we are more resilient to stress and better able to return to a calm state.

What Impacts the Vagus Nerve?

• Chronic stress or trauma

• Infection or inflammation

• Physical injury/trauma

• Poor gut health

• Physical inactivity

  
  

Supporting vagal tone can significantly enhance your ability to regulate emotions, reduce anxiety, and maintain a sense of connection.

Grounding Techniques for Nervous System Regulation

When you notice yourself outside your window of tolerance, grounding techniques can help bring you back to the present and re-engage the parasympathetic nervous system.

Simple Grounding Practices:

• Deep Belly Breathing: Inhale for 4, hold for 4, exhale for 6.

• 5-4-3-2-1 Technique: Name 5 things you see, 4 you can touch, 3 you hear, 2 you smell, 1 you taste.

• Cold Water Splash or Ice: Stimulates the vagus nerve and calms the system.

• Humming or Singing: Stimulates the vagus nerve and promotes calm.

• Vagal Breathing: Exhale longer than your inhale to cue a parasympathetic response.

• Self-Holding: Wrap your arms around your body or gently press your hands on your chest for comfort.

  
  

Grounding doesn’t erase distress but creates the internal conditions for clarity, emotional regulation, and healing.

Anchored: How to Befriend Your Nervous System Using Polyvagal Theory

For those seeking a gentle and accessible entry point into nervous system healing, Anchored by Deb Dana is an excellent resource. As a clinician and key collaborator with Dr. Stephen Porges, Dana translates complex neuroscience into everyday language and practical tools. This book guides readers through understanding their patterns of dysregulation and introduces concrete ways to return to safety and connection using the principles of Polyvagal Theory.

What makes Anchored especially powerful is its focus on compassion—not just coping. With reflective prompts, exercises, and real-life examples, Dana helps readers explore what safety feels like in the body and how to intentionally build a regulated, resilient life. This book is ideal for anyone looking to better understand themselves or support others through trauma and stress recovery.

Healing Is Possible

Nervous system dysregulation is not a sign of weakness—it’s a survival response shaped by biology and experience. With compassion, understanding, and the right therapeutic support, you can learn to recognize your patterns, expand your window of tolerance, and cultivate a life rooted in presence, connection, and resilience.

At VMA Psych, we provide trauma-informed care that respects the body’s wisdom and harnesses the science of healing. Whether you’re managing anxiety, PTSD, burnout, or simply feeling “off,” our clinicians are here to support you every step of the way, helping you reclaim balance, safety, and well-being.

Ready to feel more grounded and resilient?

Contact VMA Psych today to schedule a free intake call. Healing begins with awareness, and support is just one step away.