The "fight or flight" response is a physiological reaction that occurs in response to perceived threats. When an individual senses danger, the body releases stress hormones like adrenaline and cortisol, which prepare it to either confront the threat (fight) or escape from it (flight). This response is an evolutionary mechanism that enhances survival by increasing heart rate, redirecting blood flow to muscles, and sharpening focus. This reaction is controlled by the autonomic nervous system, specifically the sympathetic nervous system. It can be triggered by various stressors, such as predators, public speaking, or emotional distress. While beneficial in short-term situations, chronic activation of the fight or flight response can lead to health issues like anxiety and cardiovascular problems.