Question: Why when you are worried do you feel sick?

Rebecca Dewey answered on 22 Jun 2015:

If a person is anxious, this is often due to thoughts they have, which are caused by brain cells sending electrical signals to each other. If these thoughts lead the person to worry, then the brain causes the “autonomic nervous system” to function as well. This means that the brain starts sending signals to the body to tell it to prepare for “fight or flight” or just generally warning the body that something might be about to happen. This takes the form of increasing the heart rate, increasing the blood pressure, producing adrenaline, making us sweat more, etc. This might in turn cause muscles to contract, perhaps those around your gut, and that might make you feel sick (nauseous) or give you diarrhoea.