Studies have shown that drinking caffeine about an hour before working out can help boost endurance, energy, and performance, but the findings are mixed as to whether caffeine has an effect on power or strength.
Some studies have shown that drinking 150-200 mg of caffeine (similar to a Starbucks grande vanilla latte), may boost performance, while others recommend increasing it to 2.5-5 mg per kg of bodyweight (about 200-400 mg of caffeine for a 180-pound guy). But people react differently to caffeine. For some, it’s a performance enhancer; for others, it can over-stimulate them and actually decrease performance. You may want to experiment with different amounts of caffeine during practice runs and workouts to see if it’s helpful to you.
Having caffeine on days when you feel tired or need an extra boost is a good strategy, but don’t rely on it as your main energy source. If you feel tired all the time, you’re probably not getting enough energy from real food. Also, caffeine shouldn’t replace your normal pre-workout snack (see for ideas), but should complement it. Stay away from energy drinks that have chemicals, colors, or high citric acid content. Stick to coffee or tea.
Bottom line: Caffeine can be helpful for some people, but you need to see what works for you.