Adrenaline, a hormone released during stressful situations, significantly enhances physical performance by increasing heart rate, blood flow, and energy availability. This response prepares the body for a fight-or-flight reaction, improving strength, speed, and endurance in critical moments. Additionally, adrenaline boosts metabolism and sharpens mental focus, allowing individuals to react swiftly. While beneficial in short bursts, chronic exposure to stress can lead to negative health effects, hence the importance of managing stress levels for sustained performance.