4-7-8: Relieve anxiety and panic
This technique helps relieve anxiety and ease the symptoms of panic attacks. The method is simple: inhale through your nose for a count of 4, hold your breath for a count of 7, then slowly exhale through your mouth for a count of 8. Repeat this cycle 3–4 times. This rhythm can help slow your heart rate, relax your body, and restore a sense of control over your breathing.
More about the 4-7-8 technique and scientific research
link