Box breathing

It’s meant to ground you, sharpen your concentration, and leave you feeling alert but calm. 

• Push the air out of your chest, keeping your lungs empty for the count of four. Then start the tactical breathing, inhaling through your nose for a count of four, drawing air into your belly and moving up into your chest. Hold the air in your lungs for a count of four.
• The movement should feel fluid and open. Exhale smoothly, starting at the chest and moving to the belly, for four slow counts. Complete the box with a pause of four before beginning another repetition.
• Continue this technique for five minutes.