Our body's self-regulatory function

I had not quite believed the health effects of meditation, Qi Gong, yoga or other similar motionless "exercises" before. However, recently I started to change my mind. I have realized that the body actually has a major self-regulatory function, and these type of exercises (motionless) are able to let this function to work at its best.
I roughly understand that this function is mastered by our autonomic nervous system. However when we are thinking or learning something, information keeps coming into our mind (nervous system) and interfers with this system, thus it cannot work much for our inner body needs. The busier our brains are with external information, the less our body's self-regulatory function succeeds. That's why people with high anxiety or stress would suffer considerable degree of body exhaustion. Meditation, yoga or other breathing techniques can block external information's coming in by forcing our brain to rest, thus the autonomic nervous system can work full time on self-regulation.