Having not done this in some time, I found it refreshing to begin the practice again.
Measured breathing (specifically the four phase or four fold breathing technique) is very helpful for relaxation and reducing anxiety – at least for me. The practice itself is found in the cultures of India, as far as I can tell. I was first introduced to the practice from a mystical society called The Golden Dawn. Years later, when I went to a Hindu Ashram, I found they practiced the same technique.
Typically this practice is used to set up a meditation practice. A pre-cursor to meditation, if you will. The practice could be summed under the umbrella of Pranayama – which is energy control through the control of the breath.