Wake up, make a beeline for the coffeepot. it's a routine most of us can relate to. In fact, nearly 60 percent of Americans drink coffee every day. And why not? A cup of joe has long been credited with stimulating the nervous system, helping us feel more alert, better able to concentrate--not to mention more energized for a five-miler. On top of that, coffee's high antioxidant content has been attributed to reducing the risk of diabetes and heart disease, and caffeine has been linked to aiding fat metabolism and easing postworkout pain.
Then last year a new study came out that struck fear in the hearts of java junkies everywhere. The study seemed to suggest that caffeine could actually hinder performance, and one of its authors was widely quoted as saying, "Do not drink coffee before doing physical activity." What, no joe? "Caffeine may not be as harmless as we thought," says Philipp Kaufmann, M.D., a professor of cardiology in Switzerland and one author of the study. Here's what all this means for those of us who can't get out the door without a caffeine connection.
CAFFEINE JITTERS
Working at the University Hospital Zurich, Kaufmann and his colleagues found that 200 milligrams of caffeine (about two cups of coffee) decreased blood flow to the heart during exercise by 22 percent. That percentage increased to 39 for people exercising in a high-altitude chamber, which the researchers used to simulate the way coronary artery disease (CAD, or hardening of the arteries) limits the amount of oxygen that gets to the heart. No such effect occurred at rest. "When energy is used, a substance called adenosine opens the arteries to facilitate increased blood flow," says Kaufmann. "Caffeine partly blocks the effects of adenosine." Scientists have known about this relationship for a long time, but the Zurich team was the first to find that the effect was strong enough to measure, and it published the findings in the January 2006 issue of Journal of the American College of Cardiology.Since an increase in blood to the heart is necessary for aerobic activity, the findings, theoretically, suggest that caffeine could slow you down. The study's purpose, however, wasn't to look at whether caffeine could help athletes go faster or farther. Instead, it set out to investigate the effect caffeine has on blood flow to the heart. "Patients with CAD usually have decreased blood flow reserve already," says Kaufmann. "A further decrease could, in theory, be a problem for them." Furthermore, their findings suggest to Kaufmann that reduced blood flow "cannot be considered favorable" during exercise for anyone.
TAKE HEART
As frequently happens with nutrition news, the pendulum then swung back in caffeine's favor. An April 2006 Journal of Sports Science study found that caffeine had a positive impact on the performance of male distance runners. A group of caffeine drinkers, who downed 1.4 mg of caffeine per pound of body weight (a 12-ounce coffee for a 150-pound person), had a 1.2 percent improvement in an 8-K race. "They were able to maintain a higher intensity without undue fatigue," says study author Michelle Jones, Ph.D., an associate professor of exercise science at Edge Hill University in England. In the November 2006 issue of the same journal, a study examined whether or not caffeine could improve cyclists' times for a one-kilometer sprint (lasting about 60 seconds). The researchers reported a 3.1 percent improvement compared with a noncaffeinated group.CAFFEINE + YOU
So is caffeine friend or foe? It can be both. The Zurich study does carry a message of caution, says Bernard Clark, M.D., a cardiologist at St. Francis Hospital in Hartford, Connecticut. People with CAD or those at a high risk for heart disease should avoid loading up on caffeine before a run, or at minimum, check with their doctors first. "If you're not a coffee drinker," says Jones, "studies that find a positive connection between caffeine and performance aren't meant to encourage you to start."That said, if you're a regular latte sipper, there's probably no need to stop. Despite his findings on blood flow, Kaufmann says caffeine "seems not to be a problem for healthy people." And it doesn't turn 100 years of scientific research on caffeine's ergogenic properties on its head. "Caffeine's effect is both psychological and physiological," says Lawrence Armstrong, Ph.D., a leading researcher on caffeine at the University of Connecticut. "Even a little bit can make a difference. Especially after the 18-mile mark of a marathon."
MY TAKE ON IT: EHHH SOUNDS FISHY... ALTHOUGH I WILL PROBABLY TRY IT FOR MY 1 MILE AND 2 MILE RACES ON THE TRACK AND CAN'T SEE ITS BENEFIT FOR LONGER DISTANCES THAN 2 MILE... ALL I KNOW IS NOTHING ENERGIZES YOU LIKE A GOOD MEAL BEFORE A RACE
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