your heart races because your nervous system is responding to perceived danger, even when nothing is wrong. that anxiety triggers your body's ancient automatic mechanisms. Your heart rate increases to pump more blood to your muscles, generating you to fight or flee from a threat that your mind believes exists.
how our evolutionary responses to danger remain active in modern life. Your body doesn't distinguish between a real physical threat and the memory of past pain or fear of future problems. When anxiety triggers, your nervous system reacts as if you're in immediate danger, causing your heart to race even though you're safe.