The Window of Tolerance is a widely used, easily understood metaphor first created by Dr. Dan Siegal, a renowned psychiatrist. It describes the optimal functional human state—a state where we can think our thoughts, feel our feelings, and take considered actions. Within this window, we maintain a parasympathetic state, often referred to as “rest and digest” or “safe and social.” When we are pushed beyond our capacity to maintain this state, we enter a sympathetic state—characterized by flight, fight, freeze, or fawn responses—falling outside our window of tolerance. This metaphor further divides the sympathetic state: flight and fight represents hyperarousal, above the window, while freeze or shutdown represents hypoarousal, below the window.

Factors Affecting the Window of Tolerance

This window of tolerance can shrink or widen depending on the external and internal factors a person faces in life. Early childhood adversity or later life challenges such as becoming a new parent, may reduce that window, while practicing self-regulation through mindfulness may expand that window. I also want to be clear that this isn’t a perfect metaphor. There is also an aspect to this metaphor about the meanings we make of different experiences. Some forms of stressors engage our sympathetic nervous systems in positive ways as well – for example, exercise raises our sympathetic system yet promotes health, excitement is the flip side of anxiety, etc. I invite you to read more about postive and negative stressors, because the Window of Tolerance isn’t entirely synonymous with our sympathetic and parasympathetic systems.

Expanding the Metaphor

I like to extend this metaphor further. While we can expand the window so we tolerate more, I also focus on how quickly I shift from one state to another—how easily I slide out and return to that window. With my clients, we have also enriched the metaphor with elements like transparent curtains or cracking the window open for a breeze. These variations help deepen and create more meaning within the metaphor, facilitating shifts in thinking and feeling.

I appreciate this alternative conceptualization, by Juliette Young of the window of tolerance because it illustrates the process through time and as a pattern, rather than a static window that we go above and below. There is more nuance, and it visually reflects the changes in brain chemistry that occur in the calm, hyperaroused, and hypoaroused states.

Using Metaphors for Insight

The Window of Tolerance metaphor is akin to concepts like Spoon Theory, self care and pouring from an empty cup, flipping your lid, a pressure cooker metaphor for holding things in, or a runaway train to describe how quickly someone loses control. Metaphors for conceptualizing and feeling one’s way through unique patterns of action and reaction are invaluable in gaining insight into what makes you tick and understanding why you behave the way you do.

Recognizing Patterns for Greater Control

Conceptualizing a pattern rather than examining each individual incident can illustrate a broader thread running through our lives. It creates a sense of agency and control, enabling us to understand the mechanics of moving from calm to aroused, from in control to out of control. Sometimes, this reveals deeper meanings that drive patterns of losing control. Interestingly, it’s often the sense of lost control in a situation that leads to a letting go of self-regulation. Losing control of the situation often evokes past visceral-emotional experiences where one felt powerless, helpless, desperate, sad, fearful, jealous, or other challenging emotions. Since these triggered memories are felt rather than recalled in detail, the feelings can seem to arise suddenly and inexplicably.

What Can You Do About It?

There are many ways to help yourself change these patterns. Some methods focus on slowing down reactions in the moment, while others aim to down-regulate an overall chronic state of heightened awareness and hypervigilance for danger. Every time you succeed in changing your pattern during a moment of stress, your brain processes messages of safety and will jump to conclusions of danger less frequently over time. This downregulates the sympathetic nervous system in general. Conversely, by working on generalized hypervigilance and downregulating the sympathetic nervous system, you may become less reactive in the moment, allowing you to slow down that jump to the sympathetic system. These two strategies work together, and the methods overlap.

Completing the Stress Cycle

Another way to think about the in-the-moment option is “completing the stress cycle.” When we perceive danger, our brain’s flight or fight processes start like a train picking up speed. There are ways to slow it back down and come back to that neutral, safe and social, state. This can be achieved by completing the fight/flight response (e.g., doing some jumping jacks) and/or engaging the safety system (e.g., smelling the roses, hugging someone, relaxing to music, or using grounding techniques). Actively engaging the parasympathetic system down-regulates the sympathetic system automatically.

Some of the most common methods are through breath, which can seem complicated or uncomfortable to do… but it doesn’t have to be that way. Use the list above to spark some ideas. A lot of people find that they’ve tried many mindfulness tools without seeing the benefit, myself included. There is a piece we often aren’t told about, which is the perception or experience of the activity. For example, many people believe a shower is calming, yet it’s only calming for someone who chooses to experience it that way, by focusing on the moment-to-moment sensory experience of the shower. If you haven’t connected with grounding and mindfulness activities before, here may be why, and you might want to give it another try.