The stress created by a deadly threat in a survival situation, can suddenly cause your body to respond with physical and psychological (biochemical) changes to prepare you for survival. Your breathing and your heart rate will become faster, blood with fill your large muscle groups and your body will become warmer in an effort to boost physical performance. This physical arousal of your body readies you for action, and is mostly caused by the release of adrenaline in your body. It is commonly referred to as the "fight or flight" response. Whereas some physical arousal is good for effective performance, too much is a problem. If your heart rate and breathing become too fast, you will experience a degradation in your motor skills and difficulty with cognitive abilities. In other words, it wil...