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by Dr Jody Welborn

March 1, 2000

Moderation is key

As you down that steaming cup of coffee in the early morning before swim practice, or sip espresso before the first swim event of the big meet, it may cross your mind that this may not be benefiting your performance or your health. What are the facts regarding caffeine use?

Whether it is drinking a latte, downing an iced tea or drinking cola as an afternoon pick-me-up, caffeine is one of the most widely used drugs in the world. It is certainly the most comprehensively studied.

What, exactly, happens when caffeine enters the body? Caffeine is very well absorbed and peak blood levels are achieved within an hour after ingestion. It then causes a number of responses in the body. Blood pressure, heart rate, and stomach acid are increased and fatty acids are released into the blood stream. These effects may last up to 12 hours, but after about four days of use the body develops a tolerance to the effects of caffeine and the changes described are not as pronounced.

In considering the use of caffeine, as with any other drug, it is important to consider the potential adverse effects on your health. Research suggests that caffeine has no adverse health effects when used in moderation, i.e. 1-2 mugs of brewed coffee per day, or 3-5 12-ounce glasses of iced tea. Studies have looked at the possible association between caffeine use and fibrocystic breast disease, pancreatic cancer, and heart disease. Proving a cause and effect relationship is difficult, and despite numerous studies, a relationship between caffeine and these diseases has not been demonstrated. One study looking at caffeine and heart disease actually suggested that there was a slightly increased risk of death from heart disease in people who drank more than 5 cups of "decaffeinated" coffee daily!

The short-term adverse effects are well known. Caffeine increases the amount of stomach acid produced and may cause or worsen heartburn. Insomnia and anxiety can also be attributed to caffeine intake and some relate that increased heart rate or palpitations are caused by caffeine use. As well, caffeine is a mild diuretic, and dehydration may be a concern with use before long exercise sessions or racing. Some athletes may also experience abdominal cramps or diarrhea related to caffeine use and this, combined with mild dehydration, may be detrimental to performance.

In addition, some people may become dependent on caffeine and experience withdrawal symptoms such as headache and fatigue when stopped. These symptoms typically are relieved with caffeine and their severity can be decreased if caffeine intake is decreased gradually as opposed to quitting “cold turkey.” The symptoms will also improve after several days if caffeine is not restarted.

Caffeine has been shown to be a performance enhancing drug. Performance enhancing drugs have been used since the days of the Greeks and Romans, but, for some, caffeine has replaced the carafe of lion's blood used in ancient times. Caffeine has been shown to enhance performance, but primarily in endurance sports. This may be due to caffeine's ability to mobilize fat stores, encouraging working muscles to use fat as fuel, thus delaying depletion of glycogen stores. This physiologic effect is less important in short term, high intensity exercise such as sprinting. Caffeine may also alter the athlete's perception of how hard she is working, which translates into less fatigue. However, caffeine affects each person's performance differently. Some athlete's thrive on it; others cannot use it due to stomach upset or jitters.

Because caffeine enhances athletic performance, the International Olympic Committee has banned it, but in levels that are above those needed to improve performance. In order to achieve these levels a 150-pound athlete would need to drink 3-4 large cups of coffee within an hour of the activity. The estimated caffeine intake to achieve improvement in performance is 225-400 mg, which can be obtained in one 10-ounce cup of coffee.

Thus, studies have shown that a cup of coffee or a can of Mountain Dew is likely not harmful when used in moderation. There are short-term effects, both positive and negative, that should be considered before an athlete uses caffeine, and daily use is an individual preference.

Jody Welborn is a cardiologist who lives in Portland, Oregon. She holds a B.A. from the University of Oregon, and completed her M.D. at Oregon Health Sciences University. After doing an internal medicine residency at University of Texas, San Antonio, she proceeded to the University of Alabama at Birmingham for a fellowship in Cardiology. Jody is also a Masters swimmer with the Tualatin Hills Barracudas.


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