What causes the feeling of having your “blood boil” when you’re angry?
In: Biology
Our heart rate increases, along with arterial tension and testosterone production. Our stress hormone cortisol decreases. Acetylcholine is an excitatory neurotransmitter that is released and triggers muscle contractions and stimulates the secretion off other hormones. Basically anger triggers the fight or flight response of the body (other emotions such as fear can do this as well). The fight or flight response triggers the brain to shunt blood away from the digestive system and pump it toward the muscles for exertion such as fighting or running. This triggers the cardiovascular system to react, increasing the blood pressure, heart rate and respirations, pupils dilate, we perspire, adrenaline is release, our body temperature rises. This occurs until the “threat” or what is causing us to feel anger is gone.
That’s just how I understood it through nursing school. Maybe a doc can further explain.
“Blood boiling” anger is an idiomatic descriptor of extreme anger, rather than a subjective descriptor of the sensation of the experience.
Blood is mostly water, and so would be expected to have a boiling point that’s within 1 degree of water’s — 100^^o C. It’s also spread throughout your entire body, there’s no part of you that isn’t filled with blood. If your blood were to boil, you would experience extreme, unbearable pain everywhere in your body! The sensory overload from such an experience would be so overwhelming that it would likely cause your body to simply shut down (pass out).
So why do we say “blood boil” when referring to anger? It’s a reference that’s made from the observer’s point of view (not that of the angry person). Anger can cause increased blood flow to the skin, making a person appear red. As blood is warmer than skin, the increased flow also means the skin feels warmer than usual. You’ll notice the same thing when exercising. These things together have led to the development of the idiomatic use of ‘heat’ to describe anger.
Think about it. “Don’t talk to him, he’s too hot-tempered,” or “Wait for him to cool down before you ask.” It’s not because there’s literal heat involved in anger, but just that it can sometimes look like there is due to the increased blood flow to the skin.
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