Fullness of breath provides benefits which extend beyond (general) oxygenation of the blood. Typical breathing is sufficient for maintaining ‘optimal blood oxygen levels’. Breathing is rarely given much attention because it is an autonomic process. Pliability and responsiveness of ‘breath associated’ muscles and tissues is achieved and maintained through deep breathing. Deep breathing positively affects the nervous system. Breathing is surviving; functioning day to day on the autonomic level. Breathing completely is living; experiencing the fullness of each moment through the breath.

The process of breathing allows vertebrates (the subphylum of animals that includes humans) to exist on the earth. Breathing provides the oxygen that is so necessary for biological functions and functioning to occur. Breathing is a function that has been relegated to an autonomic function; meaning that the process occurs in the absence of receiving any attention. Heartbeat, metabolic, and sundry physiological processes are regulated in similar fashion. This autonomic process is involved in maintaining the functionality of the body. However, breathing benefits the body in other ways.
Typical breathing, for a human, is enough to completely oxygenate the blood. Within the lungs (average) there is a total capacity of six liters. Of that total, 1500 milliliters of volume are unavailable. This is because of solidity or the minimal-pliability of some of the breath associated structures. This leaves 4500 milliliters available for breathing. Yet, the average breath, inhaling and exhaling utilizes only 500 milliliters (tidal volume) of the available volume at a rate of 12 to 16 per minute. Not that it is a bad thing but it is not necessary for the blood to be more oxygenated than is necessary.

The autonomic nature of breathing allows the process to occur, basically, unnoticed. Unless one is exerting themselves to the point of ‘needing to breath’, it continues with minimal (negligible) observation. This is great from the standpoint of the many processes that one would need to responsible for if they were not autonomic. This is bad because of the prevalence of bad posture in conjunction with minimal breathing; these two states support each other in a continual loop less that optimal breath being supported by inadequate posture and visa-versa.
Full breaths go beyond fully oxygenating the blood. The parts of the body that supply oxygen to the body need to be adequately exercised to sustain their functionality. The average (male) adult losses up to 1 liter of lung capacity by age 65. In general, the use of minimal lung capacity becomes a detriment to lung functionality as one ages. There exercises that one can perform to maintain to pliability of the tissues and functionality of the muscles associated with breathing.
The major benefit, well breathing is beneficial overall, of full breathing is the positive manner in which it affects the nervous system. Breathing can become more reaction oriented when it is occurring on the autonomic level. The body is more on alert and the nervous system sets in motion various physiological processes in preparation for what the body interprets as a threatening situation. Full breathing stimulates the Vagus Nerve, which reduces the reactionary “fight or flight” response. This provides the benefits of slowing the heart rate, reducing blood pressure, and decreasing stress.

Breathing allows for basic functionality on the daily level. Walking, standing, sitting, usual daily tasks are all accomplished with breath comprised of that tidal volume. The minimal amount of breath that can sustain the bodily processes. However, the total body complex is benefitted when lung capacity is completely utilized. This has important implications for later life. Since breathing is necessary throughout one’s lifetime, it behooves one to be able to breath as fully and as completely as possible.
Not breathing is not an option . . . . . . .