http://www.bfe.org/

Near the bottom of the page is a button labeled-
Download EZ-Air {windows only} link below should take you right to the download.
http://www.bfe.org/store/setup.exe

it's a free shareware pgm that you can customize for you breaths/timing and use to help remind you of proper breathing - you can use the visual display or have the sound on for audio reminder.

this might be nice for anyone that tends to hold their breath when in pain or stress.