Breathing faster prepares the body to fight or run when we are frightened or upset. If there is no opportunity to fight or run then more air is taken in than is needed and over-breathing (hyperventilation) begins.

Too much oxygen and not enough residual carbon dioxide in the lungs can be toxic and set off a panic attack. These simple strategies turn down the arousal system by not taking in too much air.

Most panic attacks arrive unexpected even if there were preliminary signs. The automatic response to feelings of panic is to try to conceal them from one’s self and from outsiders. Concealing panic shuts down some parts of the body and mind and over-stimulates others. which intensifies feelings panic as the feelings come to be less and less under control.

If sensations of panic begin to feel life threatening then hyperventilation will turbocharge the panic into a full blown panic attack. Noticing the thoughts feelings and sensations with interest or just being aware of them disrupts this denial.

When anxious or frightened, don't take a deep breath. A normal breath takes in less air and reduces over-oxygenation.

breathe in through the nose
Not through the mouth as that can bring in too much air at once. After taking a normal breath hold it for a count of four before exhaling slowly. Breathing through the nose also produces nitric oxide which is calming and improves blood flow and the efficiency of oxygen uptake.

increase the time between breaths
No hurry for the next breath.- - just wait a bit longer

exhale slowly
Breathe out slowly. Breathing out is associated with relaxation. Breathing in is exciting.

say something calming
While breathing out perhaps slowly and silently say a calming word already associated with feeling peaceful .like 'relax' or 'easy'.

putting these together:

1

take in a normal breath through the nose with mouth closed

pause briefly while counting to four

exhale very slowly (mouth open or closed, whichever feels most comfortable) while silently saying a calming word

repeat the steps

repeat a half a dozen or a dozen times.

 

After practice this can be used any time to prevent panic arising or prevent it from escalating.