Understandably so, endurance athletes are always in search of a boost in energy and performance. More often than not, caffeine is the go-to for athletes. But is caffeine truly an ergogenic aid and is it safe?
According to American College of Sports Medicine, caffeine may be the most widely used stimulant in the world. It can come in many forms such as coffee, nutrition supplements, tea, soft drinks, energy drinks and chocolate. Caffeine can reach its highest levels in the blood approximately one hour after ingestion. It can have a stimulant effect on the brain as well as affect blood pressure, pulse rate, stomach acid production and fat stores. Many athletes use caffeine as a potential ergogenic aid and performance enhancer.
Caffeine may help mobilize fat stores, enabling the body to use fat as its primary fuel source. By utilizing fat as fuel, this allows the body to spare glycogen, which is an additional fuel source for the body stored in the muscles and liver. (For more on this check out Why Athletes Need Carbohydrates). By delaying muscle glycogen depletion, exercise can be prolonged enabling the athlete to go harder, longer, faster and perform more reps before fatigue.
Glycogen sparing is most crucial in the first 15 minutes of exercise. This is when caffeine can help significantly decrease glycogen depletion. Even though caffeine reaches its highest levels in the blood 45 to 60 minutes after ingestion, some research suggest consuming caffeine three or more hours before exercise is most beneficial. The reason is that caffeine may have a maximum effect on fat stores several hours after peak blood levels.
The Journal of the International Society of Sports Nutrition says that caffeine in the amount equivalent to one to three cups of coffee lowers heart rate during sub-maximal exercise, but not at near maximal or maximal exercise. The effects of caffeine were measured during dynamic leg exercise on a cycle ergometer. According to the Journal of Applied Physiology, no significant differences were noted in terms of heart rate.
Recent work by the ACSM, on well-trained athletes reported that 3-9mg caffeine per kg (kilogram) of body weight one-hour prior to exercise increased running and cycling endurance in the laboratory.