I take walks and listen to music or an audio book when I start boiling over. Or learn some video game OST stuff on guitar. Anything that kinda takes me out of myself and in a more zen or trance state.
There have been two or three times where I had a fainting spell from just pure bodily anxiety, but it's very rare and the last time I started feeling like I was about to pass out I just laid on my back and did some breathing exercises, which circumvented me waking up on the floor lol.
I won't claim to be a chronic sufferer of anxiety. Usually things are pretty chill inside but when major working or living or relationship changes occur, I certainly will have several month long phases where I need to make sure I'm not antagonizing myself with too much bullshit at once.