I would say meditate on the Lord Jesus Christ and His word. We don't have to do breathing exercises when we know Jesus is at the helm of every circumstance, as long as we are walking with Him. The enemy wants to hold us captive to his purposes and will and not the Lord's. That is why scripture says to hold every thought captive to the obedience of Christ.
2 Corinthians 10:3-5 (KJV)
3 For though we walk in the flesh, we do not war after the flesh:
4 (For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;)
5 Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;