Warm-ups and cool downs are important parts of physical activity. Warm-ups prepare the body for exercise by increasing flexibility, blood flow and range of motion to lower injury risk and improve performance. Examples include running in place and jumping jacks. Cool downs allow the body to gradually return to a resting state after exercise through slow movements like light jogging and stretching, which helps prevent dizziness and muscle problems. Both warm-ups and cool downs have benefits like reducing injury risk and aiding recovery.