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Body Image Issues 5/5: The Nervous System

A narrowed Window of Tolerance is typical in clients who are struggling with food and body image issues. In the final blog of her essential series, psychologist, psychotherapist and author Dr Nicole Schnackenberg shares tools for helping clients to soothe and regulate their physiological systems – paving the way for deeper emotional exploration, and leaving damaging safety behaviours behind.

In the previous blog post of this series, we took a brief look at how sensory profile factors can inform and impact upon food and body image concerns. In this final blog, we will build upon these ideas and bring the nervous system into the mix of our explorations with clients who are struggling with body image issues.

There are two branches of the autonomic nervous system, namely the sympathetic, energy-mobilising branch and the parasympathetic, energy-conserving branch. When driven into sympathetic ‘highs’ or parasympathetic ‘lows’, we move out of our Window of Tolerance – the state epitomised by a felt sense of safety within which we can think and feel at the same time – and find ourselves in a heightened, energy-mobilised state or numbed energy-conserving state.

For some of our clients, their window of tolerance may be narrow on account of developmental trauma, physical and/or emotional pain or other factors.

The link between a narrow Window of Tolerance and food / body image struggles

In my experience, people struggling with food and body image issues typically have a significantly narrowed ‘window’. When the Window of Tolerance is reduced, a person can rapidly and easily tip into anxiety states of sympathetic hyperarousal and depressive states of parasympathetic hypoarousal.

These sympathetic highs and parasympathetic lows are somatically and emotionally destabilising and disconcerting. So it is adaptive and understandable that we seek means to find our way back into our ‘window’. Some of us, and indeed many of the clients we are speaking of here, turn to food, including under-eating and overeating, to help us back into our ‘window’.

Initially and in the short-term, practices like self-starvation, as in the case of anorexia, seem to work well in bringing a person back into their ‘window’. So, the behaviour can become both compelling and compulsive.

This is partially due to the physiological phenomenon of nervous system habituation. Skipping one meal a day one week might be enough to bring a person up into their ‘window’ in the case of parasympathetic hypoarousal. But the nervous system will soon habituate. The following week, perhaps two skipped meals are required for the same effect. What starts off as a skipped meal here and there, or a late-night binge here-and-there, therefore, can rapidly escalate.

Increasing the Window of Tolerance

I believe that important elements of our work with these clients, therefore, are:

  • Supporting an understanding of their nervous system and particularly their Window of Tolerance
  • Supporting an expansion of their ‘window’
  • Building up a toolbox of methods for coming down from hyperarousal states, and up from hypoarousal states, without engaging in physically and emotionally detrimental behaviours like starving or purging

A key way to expand the window of tolerance is through increasing heart rate variability. I use biofeedback tools like HeartMath with clients to this end, alongside simple practices like coherent breathing, cold water exposure, and practising tolerance of uncomfortable emotional states.

I also explore with clients what might helpfully and self-compassionately soothe them during times of hyperarousal, and what might be usefully stimulating during periods of hypoarousal. This might include particular scents, pieces of music, breathing practices, choices of clothing, choices of foods and beverages, various forms of movement and so on.

Individual nervous systems are incredibly nuanced. A scent that is alerting to one person’s nervous system can be soothing to another’s. So, it is important to take time with our clients to explore what will be helpful for them personally.  

Empowerment and agency

Supporting our clients to find ways of expanding and coming into their Window of Tolerance can offer a sense both of control and agency. Knowing there are effective alternatives to bingeing large quantities of food, for example, during moments of anxiety or despair is a relief beyond measure to many.

It can be helpful for clients to carry a little list in their pockets or on their phones of approaches that stimulate both the sympathetic and parasympathetic branches of the autonomic nervous system, as a ready reminder when needed. Here is an example of such a list:

To stimulate the sympathetic branch (in times of hypoarousal)

To stimulate the parasympathetic branch (in terms of hyperarousal)

Scents – citrus, ginseng.


Tropical fruits; fruit juices; green tea.


Cold shower.


Upbeat, fast-paced music.


Jogging, bouncing on a trampoline, vinyasa yoga.


Extending the inhalation.


Breathing through the right nostril.


Loose, cool clothing.


Bright lighting.

Scents – lavender, bergamot.


Root vegetables; grains; camomile tea.


Warm bath.


Soft music with gentle, repetitive rhythms.


Yin yoga, slow walking in nature.


Extending the exhalation.


Breathing through the left nostril.


Tight, cosy clothing.


Dim/dark lighting.


With an expanded Window of Tolerance, and a toolbox of ways to come down from states of hyperarousal and up from states of hypoarousal without engaging in damaging safety behaviours like bingeing or starving, our clients are empowered in their recovery.

Once the physiological system has been soothed and regulated, there is more capacity and possibility for exploring emotional factors such as those we mentioned at the beginning of this blog series – thus bringing us full-circle.


Nicole Schnackenberg

Dr Nicole Schnackenberg is a child, community and educational psychologist: psychotherapist; yoga teacher and yoga therapist. Nicole divides her time between working as an educational  psychologist in Southend, Essex and her position as a trustee of the Body Dysmorphic Disorder Foundation. She is also a director of the Yoga in Healthcare Alliance and a trustee of the Give Back Yoga Foundation UK.

Nicole has authored books on food and body image struggles: False Bodies, True Selves: Moving Beyond Appearance-Focused Identity Struggles and Returning to the True Self  and Bodies Arising: Fall in Love with your Body and Remember your Divine Essence. She co-authored  The Parents Guide to Body Dysmorphic Disorder and co-edited Reflections on Body Dysmorphic Disorder: Stories of Courage, Determination and Hope.

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