Window of Capacity

Have you ever been introduced to the Window of Tolerance? 

It is a concept that was originally developed by the psychiatrist Dr. Dan Siegel as a way of conceptualising that our nervous systems each uniquely hold a band of optimum functioning wherein harmonious and adaptive flows of energy and information emerge from integrative processes (Siegel, 2020). 

Whilst the notion of the window has been extensively embraced and adapted in a variety of health disciplines the central tenet remains the same: “that each of us has a [tolerable window of affect] in which various intensities, sensitivities, and specificities of emotional arousal can be processed without disrupting the functioning of the system” (Siegel, 2020). 

This is a span of arousal wherein we can coherently and contextually engage with our affect (physiological stirring of emotion) maintaining the harmonious and adaptive flow of integration (Siegel, 2012). 

Most succinctly put, when we are within our window, we have a capacity to remain in contact, or in a state of presence, with our authentic sense of Self; we feel connected and calm, or safe-enough to process internal and external stimuli flexibly and congruently (Siegel, 2012).

It is this unique capacity to remain in a state of presence alongside our capacity for connection to Self, Other, and the World that leads me to use the terminology ‘Window of Capacity’. 

This semantic nuance is an important shift that highlights a compassionate approach whereby, rather than simply seeking to ‘tolerate’ intense affect, we can seek to acknowledge what we might truly have capacity for – moment-to-moment situationally and relationally.

To further our understanding of the Window of Capacity we might begin to unfold the notion neurobiologically.  That is, when we are within the window both our somatic and autonomic systems (the peripheral nervous system) are working with equilibrium;more specifically however, the sympathetic and parasympathetic branches of the autonomous system are monitoring and modifying levels of arousal even amidst increased stressors – there is a felt sense of safety.  

Importantly, when we are within the window even amidst a stressor our systems activate or deactivate in manners that allow us to respond with efficacy and efficiency and, when the stressor has past, to come back to a state of restful restoration.  This autonomic monitoring and modifying may also be viewed as the micro-adjustments our systems make moment to moment to attend to our homeostatic neuroceptive needs.  This can be seen as the window in which our systems can maintain the integrative capacity – physiologically, psychologically, and relationally – that allows us to engage with the world in a manner that is flexible, adaptive, coherent, energised, and stable (FACES, Siegel, 2020).

With this in mind, when we are outside the window, our nervous system might be working without a stable sense of equilibrium: our systems are unable to tolerate the level of arousal.  Accordingly, we may autonomously shift either into states of hyperarousal or hypoarousal where our integrative capacity to respond effectively is reduced or impaired.  In the face of a stressor our systems become confused and/or overwhelmed, and in moving into nonintegrative incoherence we then may react in manners that may not be congruent to our most authentic sense of Self.

States of hyperarousal can be seen as an arousal that exceeds our capacity to integrate experience.  This is an excessive activation of protective mobilisation (an ongoing sense of danger or dread) wherein the sympathetic branch of our nervous system may be unable to come back down into safety or engagement; this may look or feel like hypervigilance, anxiety, impulsivity, reactivity, intrusive or over thinking, sleeplessness or restlessness, fidgeting, chaos, confusion, overwhelm, and/or the like – any form of physiological, psychological, and/or relational response that may hold an abundance of movement or action.  Alternatively, we may understand this as an activated flight, flock, frenzy, fight, force, or freeze response.

More physiologically this is the release of neurotransmitters such as epinephrine and nor-epinephrine, potentially an increased release of glutamate and acetylcholine, as well as an increased release of glucose from the liver for increased energy.  Further to this physiologically there is a dilation of the pupils to allow more light and improved vision, a dilation of bronchi and faster respiration, an acceleration of the heart and a more forceful heartbeat, an inhibition of saliva glands and a dry feeling mouth, cold extremities as blood flow is moved to more central organs, an inhibition of pancreas and intestines, as well as inhibition of urinary system.  Paradoxically, whilst acute states of mobilisation may enhance immune functioning, in states of chronic sympathetic arousal there may be immune dysregulation or suppression.

Correspondingly, states of hypoarousal can be seen as an insufficient amount of arousal to integrate experience.  This is an inhibition/deactivation of mobilised protection (an ongoing sense of inescapable threat) wherein the parasympathetic branch of our nervous system may be unable to activate back into mobilisation, safety, or engagement; this may look or feel like lethargy, apathy, helplessness, hopelessness, depression, inactivity, auto-pilot, memory loss, numbness, shame, embarrassment, hiding, withdrawing, non-responsiveness – any form of physiological, psychological, and/or relational response that may hold an absence of movement or action.  Alternatively, we may understand this as a deactivated freak, feign, or flop response.

More physiologically this may be the release of neurotransmitters such as endogenous opioids and endocannabinoids, Gaba, endorphins, as well as an increased release of cortisol; this may look like the constriction of pupils that reduces vision, the constriction of bronchi and slower respiration, the reduction of the heart rate and a slowed beat, the stimulation of saliva glands and tear ducts, cold extremities as blood flow remains within vital organs.  Further to this whilst acute states of immobilisation may enhance immune functioning, in states of chronic parasympathetic arousal (specifically within the dorsal vagal complex) there may be immune dysregulation or suppression.

Importantly, it cannot be negated that when our systems, either physiologically, psychologically, or relationally, are chronically outside of our window there are increased risks for illness and disease or disorder to emerge.

Therefore, with an understanding of our moment-to-moment capacity to connect to our Self, Other’s, and the World in a state of presence, or with awareness of safe-enough and the movement within that takes us beyond our window either in hyperarousal or hypoarousal, we are better able to attune to our needs and wisely agree (ahead of time) to give ourselves space to re-enter a window of capacity and thus the integrative ability that opens us to engagement with the world in a manner that is contextually coherent.