The answer: yes, humans can be scared to death. In fact, any strong emotional reaction can trigger fatal amounts of a chemical, such as adrenaline, in the body. It happens very rarely, but it can happen to anyone. The risk of death from fear or another strong emotion is greater for individuals with preexisting heart conditions, but people who are perfectly healthy in all other respects can also fall victim.

Being scared to death boils down to our autonomic response to a strong emotion, such as fear. For fear-induced deaths, the demise starts with our fight-or-flight response, which is the body’s physical response to a perceived threat. This response is characterized by an increased heart rate, anxiety, perspiration, and increased blood glucose levels.

How does our fight-or-flight instinct lead to death, though? To understand that, we have to understand what the nervous system is doing when it’s stimulated, primarily in releasing hormones. These hormones, which can be adrenaline or another chemical messenger, ready the body for action. The thing is, adrenaline and similar chemicals in large doses are toxic to organs such as the heart, the liver, the kidneys, and the lungs. Scientists claim that what causes sudden death out of fear in particular is the chemical’s damage to the heart, since this is the only organ that, upon being affected, could cause sudden death. Adrenaline opens calcium to the heart. With a lot of calcium going to the heart, the organ has trouble slowing down, which is something that can cause ventricular fibrillation, a specific type of abnormal heart rhythm. Irregular heartbeats prevent the organ from successfully pumping blood to the body and lead to sudden death unless treated immediately.

High levels of adrenaline aren’t caused only by fear. Other strong emotions can also incite a rush of adrenaline. For example, sporting events and sexual intercourse have been known to lead to adrenaline-induced deaths.

Read the original article on britannica.com.

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