Caffeine: The Legal Performance Enhancer?

By Linda Lindsay

caffieneThe International Olympic Committee maintains a long and thorough list of substances banned for athletic use. But in 2004, they removed the psychoactive, performance-enhancing drug known as 1,3,7-trimethylxanthine from the list. The IOC wasn’t crazy; they just realized that the drug, commonly known as caffeine, had become a ubiquitous part of everyday life and culture for millions of people around the world. As a result, athletes are now permitted to consume caffeine in doses that approximate drinking about five cups of coffee per day.

In the U.S., about 90 percent of adults partake in caffeine daily, in the form of coffee, tea, cocoa, soda, energy drinks and chocolate. Caffeine not only boosts our alertness and productivity – it also makes us happy. That may be reason enough to indulge, but science is providing even more excuses to continue our daily habit; for many conditions, it appears, caffeine can actually be good for you.

In the realm of sports performance, caffeine offers wide-spread benefits, most notably the ability to boost endurance. The Journal of Applied Physiology published a study showing that 200 to 600 mg of caffeine (1½ to 4 cups of coffee) before a workout helps the body burn fats instead of carbohydrates, a condition called glycogen sparing. When glycogen – the primary form of energy in the muscles – is spared, it allows you to go longer and farther before reaching exhaustion.

A few cups of coffee prior to exercise can also blunt the perception of pain.

Though myths abound that caffeine results in fluid loss and a host of related problems, studies have proven otherwise. The American College of Sports Medicine published a 2007 study in Exercise and Sport Sciences Reviews showing that caffeine did not cause electrolyte imbalance or reduce a person’s heat tolerance during exercise. And though one might expect the diuretic action of caffeine to cause dehydration (and plenty of internet sites still say it does), researchers found that caffeine did not increase urine volume or decrease blood plasma volume.

For athletes whose sport requires both endurance and high levels of concentration, caffeine appears to improve cognitive ability as well, both during and after exercise.

Even folks who suffer from exercise-induced asthma were shown to benefit from caffeine. Large doses, equivalent to 4 to 6 cups of coffee, ingested within an hour of exercise proved as effective as an inhaler. Smaller doses helped too, reducing symptoms such as wheezing and coughing.

And if you need yet another reason to swing into your local coffee shop before your workout, studies on mice found that low to moderate caffeine intake combined with regular exercise killed off precancerous cells damaged by UVB rays. More research is needed on humans, but for now, go ahead and enjoy that pre-workout coffee. And when you’re done, you might want to have another, because studies show that caffeine can help you recover after a workout. Subjects who ingested caffeine along with carbohydrates after they exercised to exhaustion replenished 66 percent more glycogen in their muscles than subjects who ate carbohydrates alone.

Not all of caffeine’s influence on exercise is positive, however. A 2006 study found that cyclists experienced decreased blood flow to the heart 50 minutes after taking 200 mg of caffeine, prompting experts to caution people against using caffeine if they have heart disease or are heading to high altitude. How this phenomenon affects the normal population, especially in light of other endurance studies, is unclear.

Whether or not you consume caffeine to boost athletic performance, you might consider enjoying it for other reasons. In a groundbreaking study published last July in the Journal of Alzheimer’s Disease, caffeine significantly reduced memory loss in mice that were bred to develop the disease. The mice given caffeine showed a nearly 50 percent reduction in blood and brain levels of beta-amyloid, the protein found in the brains of people with Alzheimer’s. The mice not only stopped losing their memory – their brains functioned identically to mice of the same age that were not bred to develop dementia.

In other studies, people who drank a cup or two of caffeinated coffee per day showed a 30 percent lower risk of Parkinson’s, a disease that causes loss of the brain cells that produce dopamine. Decaf did not offer the same benefit. Coffee drinking was also associated with a 20 percent lower risk of gallstones.

When it comes to heart health, research has been baffling, partly because studies didn’t necessarily isolate the effect of caffeine from coffee’s hundreds of other bioactive compounds, many of which are thought to confer their own heart-healthy benefits. But in 2006, the Journal of the American Medical Association (JAMA) published a study explaining some of the mystery: the ability to metabolize caffeine is genetic – some people have the fast version of the enzyme that metabolizes caffeine, and some have the slow version. For those with the slow version, just two to three cups of coffee a day increased their risk of non-fatal heart attacks by 36 percent. Four cups a day increased the risk 64 percent. The good news is that less than 200 mg of caffeine a day did not raise the risk of heart attacks, even for slow metabolizers.

Oddly enough, whether you have the fast or slow version of the enzyme has nothing to do with how long caffeine keeps you stimulated.  People who can’t sleep at night after having an afternoon coffee are not necessarily slow metabolizers; it just means that their neural cells bind to caffeine more tightly, shutting out adenosine, a compound that normally helps us sleep. A person who’s kept awake all night by caffeine could, in fact, be a fast metabolizer. The lead researcher explains that we can feel the effects of caffeine’s stimulation, but we can’t “feel” the caffeine circulating in our blood.

Other factors that determine how long a person retains caffeine in their body include liver function, age, pregnancy, and taking certain medications, such as oral contraceptives.

The only way to find out if you’re a slow or fast metabolizer is by doing a non-invasive DNA cheek swab test (available from Consumergenetics.com.) This test may be particularly useful for women trying to conceive. Women have historically been told to avoid caffeine during conception and pregnancy. But in 2005, the Journal of Molecular Human Reproduction published a study demonstrating that only women who were slow metabolizers had an increased risk of miscarriage and infertility when they consumed 100-300 mg of caffeine per day. Women who were fast metabolizers suffered no adverse affects when consuming the same amounts.*

Men trying to conceive can happily partake in caffeine, because the same get-up-and-go they experience is also, evidently, enjoyed by their sperm. Research is still preliminary, but caffeine may benefit the roughly 30 percent of male infertility cases that are caused by low sperm motility.

Despite the many benefits of caffeine, some people just don’t tolerate it well, even in low doses. Cutting back may be wise if you have jitters, insomnia, irritability, irregular heartbeat, anxiety, or a condition that can worsen with caffeine, such as seizure disorder, fibrocystic breast disease, or intestinal or urinary disorders. (Recent studies suggest that PMS is not affected by caffeine.)

Remember that in addition to the obvious sources, caffeine can also be found in medications, coffee desserts, coffee yogurt, and even some energy-boosting candy, gum, oatmeal, and beer.

*Disclaimer: Many studies cited in this article use large doses of caffeine to produce an effect. Please use common sense when using caffeine, and consult a physician if you take medication, are pregnant, or have any kind of medical condition.



Linda Lindsay is a long-time Truckee resident who writes about health. She credits caffeine with helping her meet many deadlines.

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