A racing heart could be a symptom of supraventricular tachycardia, a condition in which your heart sometimes beats rapidly due to extra electrical signals. The problem is usually not life-threatening, and most people outgrow it. Many people with anxiety and panic attacks also experience racing hearts. It is possible to safely slow your heart when it starts racing. Things You'll Need Cold, wet washcloth Carbonated beverage Lie down and relax. If it's not possible to lie down, sit in a comfortable and relaxed position. This will help calm you down enough so your heart rate can begin to slow. Take a very deep breath; inhale as much as possible until you cannot take in any more air and then quickly exhale. Repeat until you feel your heart slowing down. Just simply breathing deeply will not work. You must take an extremely deep breath. Try inhaling for a count of ten and then exhaling. Breathing deeply will help get oxygen to your brain and restore your normal breathing pattern. Do the valsalva maneuver by close your mouth, pinching your nose and bearing down hard without exhaling any air, almost like a bowel movement. Keep straining as long as you can and then release the air and relax. This stimulates the carotid sinus nerve and slows down the heart rate. Visualize a calm and relaxing place. Lie still, close your eyes and focus on a place where you feel safe and relaxed. Redirecting your attention to something else will help calm your anxiety and get your focus off your racing heart. Place a wet and cold washcloth over your face. Putting something cold directly on your face helps slow your heart rate because your body will slow down as it tries to warm itself. You can also splash cold water on your face or dunk your face in a sink full of cold water. A bag of ice or frozen food can also be placed on your face instead of a washcloth. Quickly drink an ice cold carbonated beverage. This builds up pressure in the chest and stomach, which can help stimulate the heart to beat normally again. Tips & Warnings If trying these methods does not slow down your heart rate or you feel dizzy or weak, call a doctor immediately. This could be a sign of greater problem. Source
