The Science of Yoga and Trauma

Trauma is not just in the mind. It resides in the body- it lives in a racing heart, it lives in a tight chest, it lives in a startled response that is triggered by the tiniest sound, it lives in a body that is incapable of relaxing, of forgetting the threat, when it is gone. As psychiatrist Bessel van der Kolk put it, “the body keeps the score” (van der Kolk, 2014).

There are millions of people worldwide who carry the physical burden of past experiences that they have been unable to cope with, like war, abuse, accidents, loss, etc., and even talking about them is not enough to cure them. It’s here that yoga doesn’t enter as a fitness trend, but as a science-backed method for the recovery of the nervous system. This article looks at the effects of trauma on the body, the physiological mechanism behind yoga’s calming effect on the body, and the science behind movement, breath and healing on International Yoga Day.

Read More: Yoga: A Path to Psychological Well-Being

Trauma and the Nervous System 

It is beneficial to understand how the body’s alarm system is affected by trauma to understand how yoga helps. There are two modes in which the nervous system functions. The sympathetic nervous system is the “fight or flight” system. It releases stress hormones (such as cortisol and adrenaline) into the body, which accelerate the heartbeat, tighten the muscles, and make one ready to confront danger. The parasympathetic nervous system is the side that slows down the heart, relaxes the muscles and tells one that it’s safe to come to rest, so it’s the ‘rest and digest’ side. A normal, non-traumatised nervous system moves between these two systems depending on the situation. 

Trauma disrupts this balance. If a person experiences something too frightening, too painful, too sudden for the nervous system to deal with and get past,  they can get stuck in a chronic state of threat in the brain. The sympathetic system remains on after the threat has gone. This is why a person gets the symptoms of Post Traumatic Stress Disorder (PTSD), which is the experience one gets in a threatened situation and experiencing physiological (body) and emotional responses in other situations which are not exactly threatening. Symptoms of PTSD include hypervigilance (a constant state of alertness, as though danger is always imminent), flashbacks, nightmares, emotional numbness and failure to relax (American Psychiatric Association, 2013).

How Trauma Manifests in the Body and Mind

Neuroscientist Stephen Porges has created a theory known as Polyvagal Theory, which further elucidates this. Porges (2011) found three stages of the threat response of the nervous system. The first is the social engagement, which is when we feel safe, we connect with people, make eye contact and communicate. The second is fight or flight. When we feel threatened, we mobilise to act. The third is freeze or shutdown when it feels like it cannot be escaped, the body shuts down, feeling numb or dissociating (as if disconnected from one’s body or surroundings). These states occur spontaneously for trauma survivors, and one may find themselves feeling wired and exhausted at the same time. 

The wisdom of modern trauma research is that trauma is held within the body, and healing must involve the body. Although traditional talk therapy in and of itself is helpful, it may not be sufficient to access the physiological level on which trauma is stored. This makes it clinically important for practitioners to consider body-based practices such as yoga. (van der Kolk, 2014). 

Read More: Polyvagal Theory: A Breakdown of the Autonomic Nervous System and Social Behavior

How yoga calms the body 

Yoga is not a single activity; it’s a group of activities, including the use of physical postures (asanas), controlled breathing (pranayama) and mindful attention. All of these have influences specific to the nervous system and are measurable. They work together to restore the body to its “calm” or parasympathetic state, helping to move the nervous system away from its “alarm” state, from which many trauma survivors have fallen into. 

Yoga directly engages the vagus nerve, the longest nerve in the body, which extends from the brainstem through the heart, lungs, and digestive system. The vagal tone, or activity level of the vagus nerve, is the main highway of the parasympathetic nervous system and is a measure of the body’s ability to move from stress to relaxation. More vagal tone means quicker and more efficient recovery from stress. Slow, deep breathing, as practised in yoga, has been shown in numerous studies to directly stimulate the vagus nerve, which is the part of the nervous system responsible for the majority of functions in the gut that are not directly controlled by the brain. 

Read More: Yoga and Meditation Practitioners Deal with Negative Emotions More Effectively

Breath, Movement, and Body Awareness in Healing

Diaphragmatic breathing (breathing deeply into the belly instead of shallowly into the chest) and alternate nostril breathing help to reduce the heart rate and decrease cortisol, the main stress hormone in the body. Yoga breathing was shown to affect the symptoms of PTSD in veterans by lowering cortisol levels and decreasing symptoms, in one study, after 12 weeks of practice, and the effects continued after the yoga course ended (Staples et al., 2013). This isn’t relaxation in the abstract; it’s a change in the body.

Yoga also calls for physical movement in a certain way. A phenomenon that often occurs in trauma survivors is termed “interoceptive disconnection”, where the body has learned to tune out signals from the body itself, as the body has become an unsafe and/or uncontrollable space. Yoga starts to re-establish this relationship by focusing one’s attention on sensations in the body in a slow and controlled environment. Repeatedly practising this mindful awareness of the body assists the brain in regaining its trust in the body (Emerson & Hopper, 2011).

Red More: Yoga & Psychology: Bridging Ancient & Modern Wisdom

Yoga as Clinical Tool for Trauma 

Over the past 20 years, researchers have conducted extensive clinical studies on yoga and trauma, producing compelling findings. A gold standard scientific study (van der Kolk et al, 2014), which was a randomised controlled trial, showed that a trauma-sensitive yoga program was superior to a supportive group therapy session at reducing symptoms of PTSD in women suffering from chronic, treatment-resistant trauma. After 10 weeks, 52% of the yoga group no longer met PTSD criteria, compared to 21% of the control group. 

It is important to mention trauma-sensitive yoga separately, a form that David Emerson developed at the Trauma Centre in Massachusetts. It is not like regular yoga in several important respects. Instructors present directions as options or suggestions. No physical manipulation by the instructor of participants. Practitioners carefully select language to avoid evoking powerlessness or loss of body autonomy. The environment is orderly, predictable and consistent. These adaptations are not a byproduct; they are intentionally adapted to avoid the conditions of trauma (helplessness, unpredictability, loss of control) and to rebuild a sense of safety within the body  (Emerson & Hopper, 2011). 

Broader Mental Health Benefits of Yoga

Studies show that yoga reduces anxiety, depression, and chronic stress, which often accompany trauma. Based on results from over 1,000 participants in a 2019 meta-analysis (a study that combines and analyses results from many individual studies), there was a significant decrease in anxiety and depression symptoms for various forms of yoga; mind-body awareness and breath control were identified as active ingredients (Cramer et al., 2018). Research using measures of brain activity has also shown greater activity in the prefrontal cortex (the area of the brain associated with calm reasoning and impulse control) and decreased reactivity in the amygdala (the brain’s alarm centre, which trauma keeps in overdrive) after regular yoga practice (Hölzel et al., 2011).

Conclusion 

People have practised yoga for thousands of years to harmonise the body and mind. Contemporary science explains how yoga works and reshapes trauma care. Yoga stimulates the vagus nerve, lowers cortisol, reconnects to interoceptive awareness, and teaches the brain to remember that past threat equals present safety, and works with trauma at the place trauma lives, which is inside the body. 

It is not a substitute for mental health care, however, as with more severe or complex trauma, yoga complements therapy. However, it has one thing a chair and conversation sometimes cannot provide, a pathway back in the body that feels manageable, gentle and ultimately safe. 

References +

• American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). American Psychiatric Publishing. https://doi.org/10.1176/appi.books.9780890425596
• Cramer, H., Lauche, R., Langhorst, J., & Dobos, G. (2018). Yoga for depression: A systematic review and meta-analysis. Depression and Anxiety, 30(11), 1068– 1083. https://doi.org/10.1002/da.22166 
• Emerson, D., & Hopper, E. (2011). Overcoming trauma through yoga: Reclaiming your body. North Atlantic Books. 
• Hölzel, B. K., Carmody, J., Vangel, M., Congleton, C., Yerramsetti, S. M., Gard, T.,  & Lazar, S. W. (2011). Mindfulness practice leads to increases in regional brain  gray matter density. Psychiatry Research: Neuroimaging, 191(1), 36–43.  https://doi.org/10.1016/j.pscychresns.2010.08.006  
• Porges, S. W. (2011). The polyvagal theory: Neurophysiological foundations of emotions, attachment, communication, and self-regulation. W. W. Norton &  Company. 
• Staples, J. K., Hamilton, M. F., & Uddo, M. (2013). A yoga program for the symptoms of post-traumatic stress disorder in veterans. Military Medicine,  178(8), 854–860. https://doi.org/10.7205/MILMED-D-12-00536 
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• GABA levels: A randomized controlled MRS study. Journal of Alternative and Complementary Medicine, 16(11), 1145–1152. https://doi.org/10.1089/acm.2010.0007
• van der Kolk, B. A. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma. Viking. 
• van der Kolk, B. A., Stone, L., West, J., Rhodes, A., Emerson, D., Suvak, M., &  Spinazzola, J. (2014). Yoga as an adjunctive treatment for posttraumatic stress  disorder: A randomized controlled trial. Journal of Clinical Psychiatry, 75(6),  e559–e565. https://doi.org/10.4088/JCP.13m08561 
• Woodyard, C. (2011). Exploring the therapeutic effects of yoga and its ability to  increase quality of life. International Journal of Yoga, 4(2), 49–54.  https://doi.org/10.4103/0973-6131.85485