The emotions you feel when you see or think of the person you love causes a response in your body which jolts it into a “fight or flight” tone, a favor from our amygdala. This tone is caused by a concentrated release of norepinephrine and epinephrine from the adrenal cortex, an endocrine gland that sits on top of your kidneys. This surge of adrenaline causes increased blood to flow to your muscles, dilates your pupils, increases your heart rate, and turns off your digestive system. This sudden halt of the digestive tract can manifest the sensation we describe as ‘butterflies.’
