Tactical breathing is an easy-to-do technique that can be used in a
stressful situation to slow your thumping heart beat, reduce the tremble in
your hands, deepen your voice so you do not sound like Mickey Mouse, and to
bathe yourself with a powerful sense of calm and control. In other words,
it is a tool to control the sympathetic nervous system. Here is what is
happening inside your mind and body and why this simple breathing method
quickly restores your calm and control. For our purposes, let us divide
your body into two parts: the somatic nervous system and the autonomic
nervous system. The somatic nervous system is involved in those actions you
have under conscious control, such as moving your arms and kicking a stone
out of your path. The autonomic nervous system is involved with those
things that you do not have under conscious control, such as your heartbeat
and perspiration. As you read the last two sentences, your inhalation
and exhalation were also autonomic actions. If you had to consciously
control your breathing, you would die when you fell asleep. That said,
please take a deep breath and then let it out. With that conscious action,
you just pulled your breathing from autonomic to somatic control. Breathing
and blinking are the only two actions of your autonomic nervous systems
that you can bring under conscious control anytime you choose. As such,
your breathing is the bridge between your somatic and autonomic nervous
system. Begin by breathing in through your nose to a slow count of four,
which expands your belly like a balloon. Hold for a count of four, and then
slowly exhale through your lips for a count of four, as your belly
collapses like a balloon with its air released. Hold empty for a count of
four and then repeat the process. That is it. Short, but effective. Lt.
Col. Dave Grossman, On Combat
http://tipyomi-sender.appspot.com/showtip/Sheepdog%20Tip%20of%20the%20Day/During%20Combat/104