MuscleMagFitness.com reported that researchers at the Australian Institute of Sport found that athletes who consumed a small intake of caffeine before exercise could continue for up to 30 minutes longer than those who had not consumed it. The caffeine also enabled the athletes to increase the amount of weight lost during physical activity. It also produced a 3.5% increase in exercise capacity.
They suggest that substances in caffeine trigger muscles to use fat to fuel exercise instead of using the usual stores of carbohydrates. Other studies have found that caffeine taken during exercise can delay the onset of fatigue by up to 60%. (Intakes tested have typically been modest, ie 6-8 ounces of cola or coffee.)
Despite considerable research in this area, including the work at the Australian Institute of Sport the role of caffeine as a performance-enhancing drug is still controversial. Some of the data is conflicting, which is in part due to how the experimental studies were designed and what methods were used. However, there is general agreement in a few areas:
Caffeine does not appear to benefit short term, high intensity exercise (e.g. sprinting)
Caffeine can enhance performance in endurance sports.
Caffeine Recommendations for Athletes
If you choose to use caffeine, make sure that you have used caffeine extensively under a variety of training conditions and are thoroughly familiar with how your body reacts to this drug.