Re: Why do you sweat when you are afraid?

When a person fears or feels anxiety, the immediate inherent action is to 
get ready for the fight against the situation or run from the sight. We 
have acquired this behavior from our past ancestors who lived in forests. 
This response is a reflex action to protect against the possible danger. 
The fight or run actions require enormous strength and our system prepares 
our body for that by secreting adrenalin hormone. Eventual characteristic 
physiological changes include increased hear rate, increased blood supply 
to the muscles and to the brain, release of more glucose into the 
bloodstream, dilation of the pupils, increased breathing rate, and 
increased sweat gland activity.

Sweat glands help our body in two ways. They act as coolant and also help 
to excrete certain toxic substances through sweat. The coolant mechanism 
is through evaporative cooling. When body is in physical stress, increased 
metabolic activity in the muscle tissues lead to excess heat. It 
stimulates sweat glands to secrete more sweat, which helps to cool the 
body. Sweating while fearing is also due to the increased metabolic 
activity.