If you are interested in your breath and your health then I recommend this book
In transporting the breath, the inhalation must be full. When it is full, it has big capacity. When it has big capacity, it can be extended. When it is extended, it can penetrate downward. When it penetrates downward, it will be strong and firm. When it is strong and firm, it will germinate. When it germinates, it will grow. When it grows, it will retreat upward. When it retreats upward, it will reach the top of the head. The secret power of Providences moves above. The secret power of the Earth moves below.
He who follows this will live. He will acts against this will die.
500 BCE Zhou Dyasty Stone Inscription
If you are interested in learning more about the breath and how meditation I’ve written a Breathwork blogs here