Caffeine can enhance athletic performance by increasing endurance, reducing perception of effort, and boosting alertness. It acts as a stimulant that can elevate heart rate and improve focus, making it easier to train harder and longer. Caffeine's main mechanism involves its ability to mobilize fat stores for energy, allowing for improved metabolic performance, especially during prolonged exercise. Individual tolerance to caffeine varies, so it's essential for athletes to assess their own reactions and adjust intake accordingly.