Oxygen taken into the lungs is a life force - called prana by the yogis of India. The red blood cells moving through the lungs pick up oxygen and proceed to carry it throughout the body, charging every muscle, bone, nerve, and organ. Quite an impressive process, especially when you consider that it has been going on day and night from your first moment in the world. Fortunately, it happens without need for your conscious direction.
Breathing is not something you do. Rather, it is something that you allow. Left alone, the body will do what it needs to do, and most efficiently at that. Then why devote so much attention to it?
The answer is that we don't allow our breathing to happen smoothly and naturally. We continually do things that restrict it. Changing this tendency requires, at least initially, that we pay attention to it. Rather than adding something new, observe how you currently breathe and then find ways to remove the obstacles, the conditions, that are blocking your breathing and consequently depriving you of a full life.
Ive got to keep breathing. Itll be my worst business mistake if I dont. - Steve Martin