stress is poison for the body and mind
Studies have shown that over time, these effects on the nervous system are effective not only during a deep breathing practice. With long term practice they actually start to change the expression of genes that control the way the body reacts to stressful situations.
the stress response
The stress response, commonly known as 'fight or flight' is the body's mechanism for confronting dangerous situations. It evolved as a suvival mechanism to help us deal with life or death situations, and so when activated correctly, it enables us to meet a challenge head on, before quickly subsiding. But the continuous stresses of modern life mean that for many people their stress response system is constantly activated, and this can cause significant probems in the long term, including anxiety, depression, high blood pressure, and increased susceptibility to disease and rapid aging.
autonomic nervous system
The levels of stress hormones in the body are regulated by the autonomic nervous system, which is divided into the sympathetic and parasympathetic aspects. In times of stress, the sympathetic nervous system is activated, releasing stress hormones such as cortisol and adrenaline. Blood pressure goes up, muscles contract, and immune function goes down.
The parasympathetic nervous system on the other hand is the part of the ANS that is responsible for relaxation, repair, and maintaining homeostasis and long term health in the body. When activated the heart rate slows, blood pressure is lowered, and body can relax and repair itself. Two of the key mechanisms to stimulate the parasympathetic nervous system are deep breathing and progressive muscle relaxation. Thus the slow, relaxed and controlled nature of the movements in Taijiquan, combined with the deep, and long breathing, seems the perfect combination for this.
the vagus nerve
The vagus nerve, the longest nerve of the autonomic nervous system, is the primary nerve that controls the parasympathetic nervous system. Reseach has shown that the vagus nerve is stimulated by deep, diphragmatic breathing.
Stimulating the vagus nerve has also been shown to stimulate oxytocin, the body's hormone for compassion and caring leading some to refer to the vagus nerve as the 'nerve of compassion'
EEG analysis of practitioners of Taijiquan have shown increases in alpha, beta, and theta waves. This is indicative of a simultanously relaxed and alert state. This type of change in brain activity is not seen in 'western' forms of exercise.