Adrenaline, also known as epinephrine, is a hormone produced by the adrenal glands in response to stress or danger. It plays a crucial role in the body's "fight or flight" response, preparing the body to react quickly in emergencies. When released, adrenaline increases heart rate, elevates blood pressure, and boosts energy supplies. This hormone affects various systems in the body, enhancing physical performance and alertness. It also dilates air passages in the lungs and increases blood flow to muscles, making it easier to respond to threats. Adrenaline is often associated with intense situations, such as extreme sports or emergency situations.