A reaction time test measures how quickly you can respond to a stimulus, like a visual cue or a sound. It’s often used in sports, gaming, and even medical tests to check reflexes and brain function. The test usually involves pressing a button or clicking a mouse as soon as you see or hear something happen. Factors like fatigue, distractions, and even caffeine can affect your reaction speed. While some people naturally have faster reflexes, practice and focus can help improve reaction time over time.