[vgel]

Next time you have a panic attack: get a large bowl. Fill it with cool or cold water. Take a deep breath and dunk your face in the bowl for as long as possible, ideally 20-30 seconds. Make sure the water goes up to your upper cheeks / temples. Repeat 5, 6, as many times until the panic recedes. If it feels like it's not working, keep doing it.

This is using the dive reflex, which is a mechanism mammals evolved for swimming underwater. It slows your heart rate, redistributes oxygen, does a bunch of stuff that helps calm you down. This means it's a physiological effect: if you keep doing it, it will work. If you're panicking about how it's not working, keep doing it. You don't need to "try to do it right", if you're holding your breath and have your face underwater, over time your body moves into a state incompatible with panic. You might still be anxious, but you won't be having a panic attack. However it treats the symptom not the cause, so you need to use other skills afterwards. This skill simply allows you to use other skills from a place of strength instead of a place of panic.

Using the dive reflex for panic attacks is an idea from Dialectal Behavior Therapy.

Good luck.