Excessive caffeine consumption can negatively impact athletic performance by causing increased heart rate, heightened anxiety, and difficulty sleeping. While moderate caffeine may improve focus and endurance, too much can lead to dehydration due to its diuretic effects, impairing performance. Additionally, high caffeine intake can result in gastrointestinal discomfort, which may interfere with exercising effectively. Athletes should be cautious and consider their individual tolerance levels when including caffeine in their performance routines to ensure it enhances rather than hinders their ability.