system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the physiological cause of that deep seated anxiety lump in our chest during stressful or disheartening experiences?
gpt
The "anxiety lump" in your throat (when you're about to do public speaking, or when you're upset and about to cry), is caused by muscular tension keeping your glottis dilated to maximize air flow. The "clenched chest" or "heartache" deeper down your torso is caused by vagus nerve (which largely controls parasympathetic control of your organs) getting kicked out of "chill" mode by stress and entering "survival" mode, so it's going to tell the various organs to pump blood harder and faster, stop digesting, start producing cortisol and adrenaline, etc.