How many times have you watched someone get frightened out of nowhere, only to clutch their chest and proclaim “you nearly gave me a heart attack!”
It might be hyperbole, but we do feel that little jangle in our chest when something makes us jump.
The sensation is actually rooted in evolution; a little jump start to prepare you to physically take on an oncoming threat.
A perceived threat activates the sympathetic nervous system, an internal took that kicks us toward a fight or flight response. This is done by releasing certain hormones and influencing physiological functions.
Our adrenal glands squeeze out adrenaline (epinephrine), and that causes an instant reaction in the heart, forcing it to pump faster. That way, it can deliver more blood to your organs and muscles, which will need oxygen if you need to hoof it from a bear.
Or a murderer.
A sudden rush of adrenaline is stressful on the body, bringing nerves and anxiety with it. This results in shakiness, rapid pulse, and chest tightness, among other things, and the end result is a heightened level of alertness.
It’s a normal response to a frightening surprise, but certain heart conditions can be triggered by it.
So maybe make sure you know your friend’s medical history before you try to frighten them to death.
You don’t want it to actually work.
If you thought that was interesting, you might like to read about why we should be worried about the leak in the bottom of the ocean.