The breath is a window into the nervous system. When our breathing is shallow and fast, we are likely in a low, medium, or high-grade stressed state. When the breath is deep and slow, we are likely in a relaxed state which is ideal for healing.
Tai Chi is based on the concept of Yin and Yang - the universe is made up of opposite but balancing forces. Therefore, it’s ok to be very active and busy but we need to balance this out with rest and relaxation so that we don’t get burnt out and suffer.