Have you ever been startled by something completely unexpected? A loud bang. A car horn. Someone appearing behind you without warning. For a split second, your heart pounds. Your breathing changes. Your muscles tense. Your mind races as your body prepares to protect you. Even when you realise you're safe, it can take a few moments for everything to settle again. Now imagine that feeling doesn't disappear after a few seconds. Imagine your nervous system stays on high alert