Explanation: On top of the kidneys there are adrenal glands. Your brain sends signal to these glands and makes them release hormones. These hormones flow through the blood, making your heart beat faster.
Falling in love triggers the fight or flight reaction in the body. Epinephrine and norepinephrine are released into the bloodstream when the adrenal medulla in the brain releases catecholamines. This triggers the heart to beat faster and that is why you can feel it pumping away when you are attracted to someone.
