Your body is a self-healing organism, yet in order to heal it must be at rest, not in a state of defense or of fight. The mind must be stable and energies channeled to the area or areas in need of restoration.
Oxygen must circulate easily and efficiently. Breathing slow and steady, always through the nose, with the mind at peace; we have control over this process, allowing us to enter a state of restoration.
That control is the breath, through the nose, quiet and gentle, so quiet we are unaware of anything other a slight movement of the lower abdomen, five or six times in a minute, the air cool as it enters the nose, circulating through every cell in the body and warm upon exhalation.
This is an easy practice yet, perhaps, the most vital of all practices. Quiet breath, Quiet mind, Quiet healing.