Why You React Differently on Different Days: Your Window of Tolerance Explained

Some days, we can handle a messy inbox, tough feedback, or a sleepless night with relative ease. Other days, the same stressors tip us into panic, rage, or complete shutdown. What changes?

The answer often lies in the state of your nervous system, specifically, whether you're inside or outside your window of tolerance.

When you understand this window and learn how to work with it, you're not just managing stress, you’re building a foundation for healing, connection, and deeper emotional freedom.

What Is the Window of Tolerance?

Coined by psychiatrist and interpersonal neurobiology expert Dr. Dan Siegel, the window of tolerance describes the range of nervous system arousal within which you can function optimally.

When you’re within this window, you can:

• Feel emotions without being overwhelmed

• Think clearly and make grounded decisions

• Stay connected to others

• Remain flexible, curious, and present

• Access your values rather than survival instincts

This is the zone of regulation: not too much, not too little, where you're emotionally present but not overwhelmed, alert but not hypervigilant, calm but not disconnected.

For many trauma survivors or people living under chronic stress, the window can be quite narrow. They may find themselves frequently tipped into emotional extremes, not because they’re “too sensitive,” but because their nervous systems have learned to survive in unpredictable or unsafe environments.

Window of Tolerance, a visual guide

What Happens Outside the Window?

When stress or emotion exceeds your capacity to stay regulated, your nervous system shifts into protection mode, either revving up into hyperarousal or dropping down into hypoarousal.

Hyperarousal: Fight or Flight

This is a sympathetic nervous system response. It may feel like:

• Anxiety, agitation, or panic

• Racing thoughts, rumination, catastrophising

• Anger, defensiveness, or lashing out

• Feeling “on edge”

• Physical signs like a racing heart, clenched jaw, or shallow breath

You're wired for survival here; your system sees danger, even if it’s emotional, relational, or symbolic (like rejection or criticism).

Hypoarousal: Freeze or Shutdown

This is a dorsal vagal response, where everything slows or numbs. You may experience:

• Emotional disconnection or numbness

• Brain fog or “checked out” states

• Extreme fatigue or heaviness

• Difficulty initiating tasks or speaking

• Feeling small, flat, or hopeless

In trauma, these states often blend: frozen on the outside with panic underneath. None of this is weakness, these are survival strategies shaped by your history and your body’s attempt to protect you.

If you want gentle, practical ways to return toward regulation, my article “Finding Your Way Back Through Glimmers” may help.

What Shapes Your Window of Tolerance?

Both biology and relational experience influence your window of tolerance.

Early Attachment & Emotional Safety

Consistent caregiving teaches a child: my feelings are manageable, and I’m not alone with them.
When caregiving is frightening, unpredictable, or emotionally unavailable, the nervous system adapts: hypervigilance to threat, or numbing to survive.

These patterns often continue into adulthood until there is an opportunity for repair.

If you woudl like to learn more about attachment, please have a look at my blog Attachment After Trauma.

Biological & Health Factors

• ADHD, autism, or sensory processing differences

• Hormonal changes

• Sleep deprivation

• Illness or chronic pain

• Nutrition and blood sugar stability

These don’t cause dysregulation; they lower your threshold, making you more vulnerable to leaving your window.

Environmental and Social Factors

• Financial strain

• Unsafe or high-conflict relationships

• Caregiving roles

• Workplaces with emotional load and poor boundaries

Trauma

Trauma, especially relational, developmental, or complex trauma, often shrinks the window of tolerance. When your body has learned that connection can be unsafe, or that emotions lead to punishment or abandonment, the system stays in protection mode.

How to Tell When You're Near the Edge of Your Window

Part of nervous system literacy is learning to track your state. What does dysregulation feel like for you?

Signs of Approaching Hyperarousal:

• Noise, light, or touch suddenly feel overwhelming

• Everything feels urgent

• Quick, impulsive responses

• Tight, buzzy energy in the body

Signs of Approaching Hypoarousal:

• Feeling “floaty,” foggy, or far away

• Zoning out in conversations

• Feeling “lazy” or heavy, even if you’re well-rested

• Loss of interest in things you usually enjoy

Your body often knows before your mind does. Shifts in breath, posture, and muscle tone are early signals, tiny invitations to slow down or reach for support.

These states are not weaknesses; they’re survival responses shaped by your history and your nervous system's learning.

People who have lived with emotional abuse often move rapidly between hyperarousal and hypoarousal—cycling between panic, freeze, shutdown, and trying to stay small to avoid conflict. These reactions make perfect sense in unsafe relational environments. If you'd like to understand this more deeply, you may find Recognising Emotional Abuse helpful.

How to Regulate When You’re Outside Your Window

Grounding

Grounding brings your attention back to the here and now.

• 5-4-3-2-1 sensory grounding technique (name 5 things you can see, 4 things you can touch, 3 things you can hear, 2 things you can smell, 1 thing you can taste)

• Holding something weighted or cold

• Naming your environment out loud: “I’m sitting in my chair. It’s Tuesday, and I’m safe enough right now.”

Breathwork

Breathing can either calm or re-energise, depending on what you need.

• For hyperarousal: slow belly breathing, long exhale, or box breathing (inhale counting to 4, hold for 4 seconds, exhale for 4 seconds, repeat 4 times)

• For hypoarousal: energising breaths, sighing, or even humming to stimulate the vagus nerve

Movement

• Fight-or-flight energy (hyperarousal): shaking, dancing, walking, or punching a pillow.

• Freeze energy (hypoarousal) often shifts with gentle motion: yoga, swaying, rocking, stretching, short outdoor movement.

Co-regulation

Humans are wired for connection. Sometimes, the fastest way back into your window of tolerance is in the presence of someone safe.

• Call a friend who calms you

• Sit next to someone who feels safe, even in silence

• Voice memos offering yourself reassurance

Self-Compassion

The inner critic thrives in dysregulation. But what we need most is kindness.

Try saying:

“This is hard right now. My nervous system is trying to protect me. I can meet myself with care.”

How to Expand Your Window Over Time

While in-the-moment tools are vital, long-term resilience comes from gently widening your window of tolerance. This is a slow, steady process of healing and nervous system re-learning.

1. Therapeutic Support

• Somatic therapy helps reconnect the body and mind

• EMDR processes trauma stored in the nervous system

• Polyvagal-informed work helps rebuild a sense of safety

• Parts work (IFS) addresses the protective roles of inner parts

2. Routine & Rhythms

Regularity soothes the nervous system. This might include:

• Predictable sleep and meals

• Movement and rest cycles

• Time in nature or low-stimulation environments

3. Relational Repair

Attuned, safe relationships—whether with a therapist, partner, or friend—are powerful. Co-regulation literally rewires capacity. When someone meets you with steadiness and presence, your nervous system slowly learns: I don’t have to manage this alone.

How Shame Shapes Relational Repair

For many people with relational or developmental trauma, repairing in connection isn’t just difficult—it can feel exposing or unsafe. When shame has been part of your early environment, closeness can activate old, protective beliefs such as “I’m too much,” “I’m a burden,” or “If someone really sees me, they’ll leave.”

These shame-driven narratives make receiving co-regulation harder. Even in the presence of someone safe, the body may brace, minimise feelings, apologise excessively, or “perform” wellness to avoid disappointing others.

Understanding shame as a learned survival response—not a personal failing—is a profound part of expanding your window of tolerance. As shame softens, it becomes easier to let supportive people in, to repair after conflict, and to experience connection as regulating rather than threatening.

If you’d like to explore this more deeply, you may find Understanding Toxic Shame: Healing the Wounds of Childhood helpful.

4. Pacing and Gradual Exposure

Expanding your window doesn’t mean pushing through distress. It means dipping your toes into discomfort and then retreating when needed. Over time, this builds capacity and confidence.

A Note on Non-Linearity

Some days, you'll recognise dysregulation early and use your tools. Other days, it will catch you off guard. You may expand beautifully for weeks, then collapse again in old patterns.

This isn’t failure. It’s the nervous system doing its best with what it has. Healing is cyclical, not linear.

Final Thoughts: Your Nervous System Is Not Broken

Your reactions are not flaws, they’re adaptations.
You are not “too much” or “too sensitive.” You are someone who had to survive more than most people ever see.

And learning how to live inside your window, expanding it, resting in it, and returning to it, is an act of radical self-respect.

Want Support in Expanding Your Window?

I work with adults across Melbourne and online who are navigating trauma, burnout, emotional intensity, and relationship patterns shaped by their nervous system.

I work with adults across Melbourne and online who are ready to deepen their self-awareness and build practical tools for emotional regulation and resilience.

You're welcome to reach out:
📧 kat@safespacecounsellingservices.com.au