Breathe diaphragmatically

To calm the sympathetic nervous system and activate the parasympathetic nervous system, slow your exhalation. Stack your hands one on top of the other on your belly and count 1, 2, 3, 4, as you slowly inhale, and then slowly exhale for four. As you get competent and comfortable with that, you can start to extend the exhalation, e.g., inhale for four or inhale for six, and then exhale for eight or 10.

As you inhale, your hands rise as your tummy expands. Then as you slowly exhale, your hands shrink back towards your spine as your tummy deflates.