A warm-up routine is essential before exercise because it prepares the body physically and mentally. It increases heart rate, enhances muscle elasticity, and improves joint mobility. This gradual increase reduces the risk of injury and helps optimize performance during workouts. Additionally, warm-ups mentally prepare individuals, making them more focused and ready for the upcoming physical activity. Incorporating light aerobic exercises and dynamic stretches during a warm-up can also improve blood flow to muscles, making them more responsive to the demands of the workout.