3. Use cold water.
This method is effective because it stimulates the vagus nerve that, above all, helps to control heart rate. If you feel that your heartbeat is fast try to splash cold water on your face. You can also immerse your face in a sink or large bowl filled with cold water. Keep your face under water for as long as you can.
4. Bear down.
This technique is close to the Valsalva maneuver described above. It consists of 2 steps:
- Clench your stomach muscles and your anal sphincter;
- Bear down as if you are having a bowel movement.