Consuming too much caffeine can adversely affect fitness in several ways, including increased heart rate and dehydration. Excessive caffeine intake may lead to jitteriness, anxiety, and disrupted sleep patterns, which are detrimental to recovery and overall performance. These effects can hinder focus during workouts and prevent individuals from achieving optimal results. Moreover, relying too heavily on caffeine can create dependency, impacting performance negatively when not consumed. Moderation is key to maximizing the benefits of caffeine in enhancing performance without adverse effects.