There are many ways to activate the parasympathetic nervous system (PNS) when you are safe, but you are feeling tense, stressed, or anxious.

• The most effective way is to spend time with people you trust if you can. When we are with friends and people who care about us, we feel supported and safe; we can talk about our concerns and receive understanding and support.
• When groups of people are suffering, they will often sing, laugh, and cry together. All of these actions involve a deep breath and a long outward breath; this stimulates the vagal nerve, which runs from the lungs, heart, and gut to the emotional center of the brain and activates the PNS. Information moves in both directions along the vagus nerve; when the PNS is active, it slows the heart rate and breathing, stimulates digestion, and the immune system.
• When you are alone, you can activate the PNS by deliberately taking a relaxed breath in and breathing out slowly. You can use counting to help with the timing by inhaling for three or four seconds and exhaling for six to eight seconds. Controlled breathing technique
• Practicing yoga, mindfulness meditation, Ti Chi, and similar activities stimulate the PNS.
• When you are not in danger but still worried or anxious, it can help to tune in to the present. Take a moment to listen to the sounds as they occur in the present, look around, smell the air, and feel the sensations in the body and on the skin. Focusing on this sensory information reorientates the mind to the fact that there is no imminent danger.
•  Anxiety is fear produced by worry or concern when there is not any immediate danger so It can be useful to remind your self of the present reality and reassure yourself, as you would with someone is frightened but safe, by repeating simple statements to yourself such as -
• • “I am safe,
  •   I am well, well enough
  •   I am grate.ful/comfortable/happy”

As you repeat these statements allow the truth of them to soak in to your body and mind.