How your brain and body reacts when facing a threat

The threat of death, serious bodily harm, rape or kidnapping is significant.  When faced with that level of threat, you will feel fear - no matter how fit, strong, or capable you are.

The fear response is a survival response that begins in the brain and spreads throughout your body.  This response is a survival response because it makes adjustments to your body that assists in defending you from a threat, however these changes can also make it more difficult to defend yourself.  

Fear begins in the part of the brain called the amygdala. When faced with a threat, it activates areas involved in the fight or flight response, triggers release of stress hormones and activates the sympathetic nervous system.

All this activity results in changes to our bodies like a hyperalert brain, dilated pupils, accelerated breathing, increased heartrate and blood pressure. Blood flow centers around vital organs and away from extremities. 

If the threat is not yet extreme to completely shut down higher brain functioning, the hippocampus and prefrontal cortex can help the brain interpret the threat and help you process whether a perceived threat is real.

This is why it is essential that you pay attention to your surroundings, prepare and train for possibly dangerous incidents, and avoid behavior that can put you at risk of being ambushed and overwhelmed by the stress response and not be able to process what's going on, take reasonable actions, and survive.