It’s well-known that caffeine can increase performance, but don’t exaggerate. Caffeine over-dose can significantly affect your training performance and times in races.
Caffeine can improve your performance, but it can also make you jittery and even upset your bowels. Everybody has a different sensitivity to caffeine, so make sure you find your ideal amount before playing around with its use in training.
Never go to races and do something you haven’t done in training when it comes to your fueling and hydration strategies. If you drink coffee or tea every day you’ll be less sensitive to the impacts of caffeine supplements. The amount you consume will depend on the length of your race or training effort and your weight.