Movement increases sensation and reduces over-reactivity to internal sensations
There is a network of structures in the brain referred to as the “default mode network” (DMN) or “default state network.” The DMN gives you an internal sense of your self: it processes sensations that you feel in your body, coordinates emotions and thinking, and allows you to reflect on your own emotional and physical state.
As renowned psychiatrist Bessel van der Kolk describes in his landmark book The Body Keeps the Score, brain scans of patients suffering from PTSD show startlingly low activation of these self-sensing areas of the brain. In response to the trauma they experienced, people learn to shut down the areas of their brain that sense their internal state and emotions so that they can avoid feeling the terror of past events.
Sadly, shutting down the DMN in order to avoid feeling emotions also results in not being able to sense the body accurately, sometimes to the point of not being able to feel entire areas of the body. Stress and emotions don’t exist only in the mind; they involve the release of hormones, contraction of muscles throughout the body, changes in heart rate and breathing, and how we sense and react to these internal changes. Babette Rothschild eloquently sums it up in The Body Remembers: “Each emotion is the result of interplay between the sensory, autonomic, and somatic nervous systems interpreted within the brain’s cortex.” When PTSD patients shut down their emotional processing to avoid reliving their trauma, they also shut down their ability to sense their bodies.
Another adaptation of the sensory system in response to trauma is becoming over-reactive to internal physical sensations. A slight speeding up of the pulse or shallowing of the breath in response to a mild stressor can quickly escalate into a full-blown panic attack or asthma attack. People with PTSD sense their physiological stress response kicking in, and feel as though they are experiencing the traumatic event all over again.
Learning how to sense the body internally, and learning how to correctly interpret those sensations, is a critical part of recovery from trauma. Recognizing what we feel and why we feel that way gives us the ability to regulate our emotions and control our lives. Having conscious awareness of what’s going on in our minds and bodies allows us to choose something other than our habitual reactions; we can notice our physiological sensations for what they are and allow ourselves to calm down instead of becoming overwhelmed. And being in tune with our interoception (our sense of the internal state of our body) allows us to know what we need and to take care of ourselves.
Sensory neurons in our body respond to stimuli, like changes in heart rate or breathing, damage to cells, movement in our joints, and contraction or stretching of our muscles. These sensory receptors then send information about the change in our internal state to our brain for processing. If I ask you to notice how your second and third toes feel, can you? Did you instinctively move your toes in order to feel them?
So in order to improve internal awareness, it is most effective to create change within the body, because change stimulates the sensory system; this is one reason why movement helps in trauma recovery. Slow, conscious movement that creates gentle change within the body and gives you time to process the sensations you feel is best. Fast or intense movement can be overwhelming and stress-inducing, and does not allow the time for noticing and processing internal sensations. Van der Kolk notes that in his studies using yoga for trauma therapy, a yoga program involving intense movements had a high dropout rate, while the program that moved very slowly was far more successful.