By Coach Dawn Elder
We all look for that extra something to give us the edge on the competition. One common way to do that is to use caffeine before or during the race. Caffeine continues to be one of the most studied and consumed ergogenic ingredients. Researchers are constantly re-designing studies to get a clear indication of how caffeine improves performance. It is important to know how caffeine actually works in our bodies as well as how it can help or harm your next race.
45-60 minutes after ingestion, the caffeine reaches peak blood levels. Once in the blood stream, caffeine causes a number of responses in the body. Caffeine is well known for it's stimulant effects on the brain, but there are a number of other physiologic effects that occur. Blood pressure, pulse rate, and stomach acid production are increased, fat stores are broken down, and fatty acids are released into the blood stream. These effects can last from a few hours to as long as 12, but within 4 days of regular use, the body develops tolerance to many of the effects of caffeine. For example, although caffeine increases blood pressure and pulse in a first time user, a regular user will not experience any significant change.
Despite considerable research in this area, the role of caffeine as a performance enhancing drug is still controversial. However, there is general agreement in a few areas:
1. Caffeine does not appear to benefit short term, high intensity exercise (eg. sprinting)
2. Caffeine can enhance performance in endurance sports.
Glycogen is the principal fuel for muscles and exhaustion occurs when it is depleted. A secondary fuel, which is much more abundant, is fat. As long as there is still glycogen available, working muscles can utilize fat. Caffeine mobilizes fat stores and encourages working muscles to use fat as a fuel. This delays the depletion of muscle glycogen and allows for a prolongation of exercise. The critical time period in glycogen sparing appears to occur during the first 15 minutes of exercise, where caffeine has been shown to decrease glycogen utilization by as much as 50%. Glycogen saved at the beginning is thus available during the later stages of exercise. Although the exact method by which caffeine does this is still unclear, caffeine caused sparing in all of the human studies where muscle glycogen levels were measured. The effect on performance, which was observed in most experimental studies, was that subjects were able to exercise longer until exhaustion occurred.
In addition to the beneficial effects on muscle, caffeine may alter the perception of how hard you are working. During testing, athletes are asked to judge their effort, which is referred to as the rating of perceived exertion (RPE). Some studies have yielded significantly lower RPE's -- less fatigue -- when the athlete used caffeine. Other studies have not found this effect. Obviously, the RPE is very subjective, and there are many things that may influence it.
Before planning all your workouts around the nearest coffee shop there are a few things to take into consideration. Caffeine may not have the same effect on everyone. Some individuals are more or less sensitive to it. Some athletes may also experience gastrointestinal discomfort or challenges with caffeine. Also, know what gels or drinks contain caffeine so that you don't unknowingly double up on the dose. Try it in training under different scenarios to know how you will respond. If you don't have any adverse effects, use it in your race nutrition plan as a safe and effective way to pursue that "something extra".
For questions or comments contact Coach Dawn Elder at dawn@trisitionarea.com
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