Understanding the Window of Tolerance

In the pace of modern life, it’s easy to find ourselves swinging between feeling overwhelmed and feeling shut down. One moment we’re steady and present, the next we’re anxious, reactive, or strangely numb. The concept of the Window of Tolerance offers a simple but powerful way of understanding why this happens.

The term was introduced by Dr Dan Siegel in 1999 in his book The Developing Mind. Drawing on neuroscience, attachment theory and trauma research, he described the “window” as the zone in which our nervous system is regulated enough for us to think clearly, feel our emotions, and stay connected to ourselves and others. When we’re inside this window, we can respond to life rather than react to it.

When we move outside it, things change. If we go into hyperarousal, we may feel anxious, angry, overwhelmed or on edge — heart racing, thoughts spiralling. If we drop into hypoarousal, we might feel flat, numb, disconnected or withdrawn. Both are protective nervous system responses. Neither mean we’re broken. They simply show that our system is doing its best to cope.

Our window is shaped by our history. Trauma, chronic stress, attachment patterns, sleep, health and lifestyle all influence how wide or narrow it feels. Some people can tolerate high levels of stress and stay regulated; others may find relatively small triggers push them outside their window. Understanding this can be deeply relieving — it moves us away from self-criticism and towards curiosity.

In my work, I often introduce the Window of Tolerance as a way of helping clients make sense of their emotional experience. We explore together what it feels like to be inside their window. What are the signs? What helps them stay there? We also gently identify what pulls them out — perhaps criticism, conflict, overstimulation or certain relational dynamics.

From there, we build awareness and tools. Breathwork, grounding practices and somatic awareness can help when someone tips into hyperarousal. Gentle movement, connection, or self-compassion can support someone who has shut down. The aim isn’t to eliminate strong emotion — it’s to increase capacity. Over time, the window can widen.

This is where relational work matters too. Our nervous systems regulate in connection. Safe, attuned relationships — including the therapeutic relationship — can gradually expand tolerance and build resilience. Practices like yoga, mindfulness, time in nature and meaningful connection all support this process.

For me, the Window of Tolerance offers a compassionate lens. It reminds us that our reactions are adaptive, even when they’re uncomfortable. And it gives us a framework for growth — not by forcing change, but by building awareness, safety and capacity.

Expanding your window isn’t about becoming unshakeable. It’s about recovering more easily, staying present for more of your life, and meeting yourself with understanding along the way.