Millions of people, including athletes, are inseparable from their coffee-drinking habit. In a world where a "mere" 40-hour work week is considered leisurely by some, the pick-me-up that caffeinated coffee delivers has led to the proliferation of countless chain and local coffee shops in every corner of America. Runners, ever looking for some extra pep in their step, are naturally curious about how drinking coffee affects them during their jaunts.
History of Caffeine and Athletics
Until 2004, blood levels of caffeine exceeding 12 mcg per milliliter was considered a doping offense by the International Association of Athletics Federations, the international governing body for track and field. That year, however, the IAAF removed caffeine from its banned-substances list owing to research suggesting that caffeine levels above this threshold actually impaired performance. Since then, the IAAF continues to monitor athletes' caffeine levels, but does not suspend athletes for using it in any way.
Pharmacology
Caffeine is in the chemical class of compounds called methylxanthines, and is a metabolic and central-nervous-system stimulant. It quickens reaction time and in general improves a number of cognitive processes, according to News-Medical.net. Studies of the effects of caffeine on memory and other brain functions, however, are equivocal. Notably, the half-life of caffeine -- that is, the time it takes to eliminate one-half of the caffeine in the bloodstream from the body -- is usually about 4.9 hours, but varies widely from person to person. According to the Mayo Clinic, an 8-ounce cup of brewed coffee contains between 100 and 200 milligrams of caffeine, roughly three to four times that of a 12-ounce soda.
Physiological Effects
A study of high-caliber 1,500-meter runners that was published in "The British Journal of Sports Medicine" demonstrated that pre-run ingestion of caffeine resulted in faster 1,500-meter times, a faster finishing sprint and increased oxygen utilization. A review of the available literature by L.M. Burke in 2008 strongly suggests that caffeine improves athletic performance across a range of endurance events, including running, while its effects on strength- and power-based events are less clear.
Potential Hazards
Drinking large amounts of caffeinated coffee may carry an increased risk of developing a number of acute and chronic health problems. According to registered dietitian Karen Collins, a high intake of caffeine may result in nausea, headaches, sleep difficulties, heart palpitations and increased anxiety. Collins recommends drinking only moderate amounts of caffeine -- no more than 300 mg a day, or the equivalent of two or three cups of coffee.
References
- "British Journal of Sports Medicine"; Effect of Caffeinated Coffee on Running Speed, Respiratory Factors, Blood Lactate and Perceived Exertion During 1500-m Treadmill Running; J.D. Wiles, et al.; June 1992
- IAAF: Q & A: 2009 Prohibited List
- IAAF: World Anti-Doping Code: The 2011 Prohibited List
- News-Medical.net: Caffeine Pharmacology
- MayoClinic.com: Caffeine Content for Coffee, Tea, Soda and More
- "Applied Physiology, Nutrition, and Metabolism"; Caffeine and Sports Performance; L.M. Burke; December 2008
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