Sit or lie down
Breathe slowly and deeply
Exhale longer than you inhale
Relax your shoulders and jaw
Unclench your hands
Try paced breathing
Use a calm, quiet environment
Drink water
Avoid caffeine and nicotine
Cool your face with cold water
Practice meditation or mindfulness
Reduce physical activity
Loosen tight clothing
Focus on a steady, slow rhythm
Seek medical help if the fast heart rate is severe, persistent, or accompanied by chest pain, fainting, or shortness of breath