dont stop breathing during a panic as this can trigger the false suffocation alarm, making the panic worse
the best breathing is deep and slow, with the muscles relaxed, empty the lungs as much as you can, then fill them right up with air, the chest and stomach both go out and come in together, best to breathe thru the nose
keep relaxing the muscles, dont tense up or fight back
accept what is happening and allow time to pass
long term anxiety sufferers often have poor chest expansion, due to cronic muscle tension, ask doc to check your chest expansion