Humans blush when veins in the face respond to the chemical adenylyl cyclase, which allows adrenaline to act on blood vessels and cause redness. When the blood vessels dilate, or open up, more redness appears in the face as blood just beneath the skin. Drinking alcohol and sexual arousal also cause face redness, but blushing from embarrassment is a unique biological phenomenon based on an adrenaline response.Continue Reading
Blushing is similar to a "fight or flight" response in the body, even though blushing only occurs in the face. Adrenaline speeds up the heart rate when humans show embarrassment, and this accelerates the redness response of the face.
A study done in the Netherlands in 2013 suggests people who blush are more honest about their feelings because blushing signals genuine regret over an incident. A study published in 2011 in California determined people who blush may be more genuine and better romantic partners because of their "pro-sociability," or favored social behavior, toward others.
The fear of blushing is called erythrophobia, which may be cured by an endoscopic thoracic sympathectomy. The surgical procedure severs the nerve connections that trigger the blushing reflex. A common side effect of the surgery is facial sweating, so instead of turning red, someone's face may sweat instead.Learn more about Blood