Sarina R. Saturn, PhD
How trauma affects the body and brain
Trauma leaves enduring marks on the brain and the body. All traumatic experiences recruit the stress response, which involves an array of physiological and hormonal changes that impact the central and peripheral nervous systems. In the short term and in moderation, the stress response is designed to aid in safety and self-preservation during threatening events. The stress response includes the release of stress hormones from the adrenal glands. These stress hormones include cortisol, adrenaline, and noradrenaline. During a threatening event, they are responsible for increasing cardiovascular tone, boosting blood pressure, and mobilizing stored energy into muscle to allow for action. These stress hormones, in turn, provide feedback to the brain and influence brain areas that are responsible for emotional and cognitive processing. During trauma, permanent physiological and psychological changes are carved into the brains and bodies of victims due to an overdrive these physiological events.
Traumatic stress has been shown to dramatically change the shape and properties of neurons, the cells that transmit and receive information nervous system. The amygdala is the emotional core of the brain, and it is under strong inhibitory control by the neurotransmitter GABA (gamma-aminobutyric acid). Chronic stress and stress hormones have been shown to make amygdala neurons grow and become more excitable by decreasing GABA-mediated inhibition. The amygdala becomes primed to make new connections, as well. Importantly, the opposite occurs in regions of the brain responsible for learning, memory, planning, and concentration, such as the hippocampus and prefrontal cortex, in that trauma can cause neurons in these areas to shrink and lose connections. Therefore, trauma can make our brains wired to be more emotionally triggered and less cognitive and collected.
As a result, trauma can lead to post-traumatic stress disorder with triggers bringing the past to the present mind. The destructive emotions can also lead to mental disorders, such as depression and anxiety, and unhealthy coping behaviors, such as substance abuse, overeating, violence, and more. Trauma also lives in the body and can lead to an array of medical issues. The heart is prone to high blood pressure, high cholesterol, and heart attacks. The digestive system can experience stomach cramps, irritable bowel, diabetes, and weight fluctuations. Moreover, the immune system has difficulty warding off viruses and bacteria, leading to more illnesses and slower recoveries. In addition, the reproductive system is affected, leading to decreases in sexual drive and fertility. Other areas, including the skin, muscles, and joints are also negatively influenced by trauma.
The autonomic nervous system is the part of the peripheral nervous system that controls bodily functions that are normally outside of conscious control and it is comprised of the sympathetic and the parasympathetic nervous systems. Distinct autonomic physiological states accompany different emotional states and the characteristics of autonomic activation indicates of how, physiologically, an individual is responding to the environment.
The sympathetic nervous system is in control of what is commonly known as the fight-or-flight response, preparing the body for physical action in a potentially threatening environment, which includes the stress response. The parasympathetic nervous system takes over when there is no environmental threat present, and is often referred to as the rest-and-digest response. A marker of increased PNS function is variability in heart rate during the breathing cycle and an index of the vagus nerve brake on the heart. The vagus nerve is an important portal through which the body and brain communicate with each other. Low vagal tone is related to emotional disorders, obesity, and heart disease. High vagal tone is related to adaptive emotion-regulation strategies, social connectedness, and positive emotions.
How yoga may help with the healing
Yoga provides powerful tools to help overcome the deleterious effects of trauma. Importantly, yoga has been shown to decrease levels of stress hormones, such as cortisol, as well as yield anti-depressant effects. Yoga centers the mind and the breath and body work brings practitioners to the present moment, thereby focusing attention via the prefrontal cortex activation, as many trauma survivors need to be rescued from living in the emotional past. The breathwork provides huge health benefits by dampening sympathetic arousal and recruiting parasympathetic calming. Trauma victims have been shown to have difficulties with vagal modulation, and yoga can help by lowering blood pressure and recruiting the vagal brake on the heart, thereby boosting vagal tone.
The mindful and meditative aspects of yoga can lead to brain alterations to counteract the effects of trauma. Indeed, yoga has been shown to boost GABA activity, which is decreased by trauma. Mindful attention has been shown to impact amygdala activity during emotional stimuli. It has also been shown to boost levels of gray matter in the hippocampus and frontal cortex, the same areas damaged by severe stress. Enhanced brain connectivity is another gift of meditative practice.
Additionally, yoga asana movements can help move trauma through the body. This takes place through muscular and joint movement, building physical strength and flexibility, and connecting the mind with the body. When the movements are done with others, a sense of belongingness manifests itself. Social bonds increase levels of oxytocin, which is an important neurotransmitter and hormone for building trust, affection, and community. Oxytocin has also been shown to dampen the stress response in order to allow people to step outside their personal narratives and connect with other people around them.
All the components of yoga combine to offer a potent and effective practice for healing from, and coping with, trauma. The combination of breathwork, mindfulness, and movement provide powerful medicine for treating the damaging effects of trauma. Trauma can lead to devastating consequences to the body and the brain. Yoga has the power to counteract this damage by offering potent therapy with strong physiological benefits.
References / Further Reading
Bremner, J. D. (2006). Traumatic stress: effects on the brain.Dialogues in clinical neuroscience,8(4), 445.
Emerson, D., Sharma, R., Chaudhry, S., & Turner, J. (2009). Trauma-sensitive yoga: Principles, practice, and research.International Journal of Yoga Therapy,19(1), 123-128.
Emerson, D., & Hopper, E. (2011).Overcoming trauma through yoga: Reclaiming your body. North Atlantic Books.
Keltner, D., Kogan, A., Piff, P. K., & Saturn, S. R. (2014). The Sociocultural Appraisals, Values, and Emotions (SAVE) Framework of Prosociality: Core Processes from Gene to Meme.Annual review of psychology,65, 425-460.
Luders, E., Toga, A. W., Lepore, N., & Gaser, C. (2009). The underlying anatomical correlates of long-term meditation: larger hippocampal and frontal volumes of gray matter. Neuroimage, 45(3), 672-678.
Lupien, S. J., McEwen, B. S., Gunnar, M. R., & Heim, C. (2009). Effects of stress throughout the lifespan on the brain, behaviour and cognition.Nature Reviews Neuroscience,10(6), 434-445.
Rodrigues, S. M., LeDoux, J. E., & Sapolsky, R. M. (2009). The influence of stress hormones on fear circuitry.Annual review of neuroscience,32, 289-313.
Sahar, T., Shalev, A. Y., & Porges, S. W. (2001). Vagal modulation of responses to mental challenge in posttraumatic stress disorder. Biological psychiatry, 49(7), 637-643.
Sapolsky, R. M. (2004). Why zebras don't get ulcers. 3rd edition. New York: WH Freeman.
Porges, S. W. (2007). The polyvagal perspective. Biological psychology, 74(2), 116-143.
Thirthalli, J., Naveen, G. H., Rao, M. G., Varambally, S., Christopher, R., & Gangadhar, B. N. (2013). Cortisol and antidepressant effects of yoga. Indian journal of psychiatry, 55(Suppl 3), S405.