Caffeine can positively affect athletic performance by enhancing endurance, increasing alertness, and improving reaction times. It stimulates the central nervous system, leading to heightened energy levels and reduced perceived exertion during exercise. Caffeine can also mobilize fatty acids from fat tissues, making them available for energy, thereby sparing glycogen stores during prolonged activities. However, individual responses to caffeine can vary, and excessive intake may lead to side effects like jitters or increased heart rate. Moderation is key to maximizing its performance benefits.