The information here comes from a recent workshop I attended with Sue Jones, sponsored by The Breathing Room yoga studio in South Portland, Maine. This is an excerpt of a letter I wrote to a friend who I thought might benefit from regular yoga practice.
Breathing and movement combine to help build important pathways that may not have formed in some individuals. Early childhood experiences or trauma at any time of life can interrupt the immune, emotional, nervous and hormonal systems from behaving the way they should. All 4 systems that are impacted at once when illness, trauma and fear are present. Nothing happens in one system that does not affect the other 3.
Memories are suppressed or destroyed by chronic levels of cortisol over time. Few recollections of childhood and difficulty learning are two possible effects of overproduction of cortisol as an overabundance of stress hormones and glutamate physically damage the hippocampus area of the brain. When the amygdala part of the brain hijacks the networks with fear of survival issues that relate way back to the early years of life and things you can't even remember that still live in the body and memory somewhere, new learning becomes very difficult.
This is a challenge to change. Lack of certainty, lack of control and lack of information exist in all people's lives and cause stress, but people who have these trauma memories have brain and neurotransmitter activity that overrides their ability to respond to those 3 triggers. Yoga is proving to be a healing force. Moving the diaphragm is the first step to changing those responses, which is WHY we are told to breathe deeply. Acetylcholine which is produced in skeletal and muscle movement has a calming influence and is also crucial in the forming of memory and reduces inflammation as well. It is released by the vagus nerve through abdominal breathing and the combination of breathing in sync with movement.
This is why yoga works to help restore balance.