Question: Why do we sweat when we're nervous?

Rebecca Dewey answered on 22 Jun 2015:

If a person is nervous, this is often due to thoughts they have, which are caused by brain cells sending electrical signals to each other. 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, and making us sweat more, etc. This will prepare us for needing to keep cool while running or fighting.