Four steps
Temperature
Change the temperature of your face to calm down quickly. Hold your breath and dip your face into a bowl of cold water. Another option: soak a cloth in cold water and press it to your face.
Intense exercise
Use physical activity to calm an overactivated mind. For 20–30 minutes, do intense exercise: running, jumping, brisk walking, playing with a ball, and so on.
Paced breathing
Make your breathing deeper and slower, with a longer exhale than inhale. Breathe with your belly and diaphragm, not your chest.
Paired muscle relaxation
Use progressive muscle relaxation: tense each muscle group in turn for 10 seconds, then release.