The breath is often revered as a connection to Spirit. The Latin word spiritus means “breath.” In English, the word “inspire” means to uplift. The word “expire” means to run out of life and die. “Inspiration” implies an energizing source that animates our mind-body complex, and “expiration” is letting go of such connections to the mind-body complex to rest in absolute consciousness. Every breath cycle is a dance of birthing creation on the in-breath, and surrendering this creation to the infinite being-ness on the out-breath.
The impulse behind this movement of the breath is a force called prana. This prana drives the breath through our waking and sleeping hours. If we average 15 breaths a minute, then over the course of a 24 hour periods we would have breathed 21,600 cycles! You are not the breather. You are too busy during your day to pay attention to your breath let alone breathe yourself. The prana flowing through your neurons, your lung tissue, blood cells, intercostal muscles, and diaphragm has the intelligence to support life in you without your conscious breath to breath consent.
Prana is more than "life force". It is an intelligent organizing life force. To meditate on the breath is to connect more deeply to the impulse of prana behind the breath. To connect with prana is to unite with this ever present organizing intelligence that "breathes" all life forms.
To closely observe our breathing pattern is to witness our relationship to this intelligent life force. Life experiences that leave harsh mental impressions in the mind -body complex can restrict the natural rhythm of the breath. Just notice if you are in pain (mentally or physically) how this will disrupt the natural ease of the breath. The breath will tell us if we are out of balance. The breath is one of the more accessible portals we have to the power of creation.
Exercise: Sitting upright and comfortable and watch your pattern of breathing to note if you tend to break the cycle of breathing with pauses at the end of the inspiration or the expiration. Note if it is more difficult to maintain an even flow on the inhalation or the exhalation. Is the breathing shallow or is it deep from the diaphragm? Signs of relaxed breathing is that it is deep from the abdomen, even duration of inhalation and exhalation, smooth flow with no pauses, and is quiet. The quality of breath is a reflection of the relationship that we have with the flow and intelligence of creation.