Question: why do humans blush

Kate Dobson answered on 20 Nov 2014:

Had to look this one up….When you’re embarrassed, your body releases adrenaline that speeds up your breathing and heart rate (to prepare you to run from danger). Adrenaline causes your blood vessels to dilate (get wider) to improve blood flow and oxygen delivery. When you are embarrassed, the veins in your face respond to a signal from the chemical “adenylyl cyclase”, which tells the veins in your face to allow the adrenaline to work, allowing more blood to flow through them and mking your cheeks go red.