Caffeine is a stimulant that occurs naturally in tea and coffee. It is also typically added to sodas as well as pain reliever medication. Caffeine stimulates your central nervous system, resulting in a temporary boost in alertness, energy level and overall mood. Caffeine is also a diuretic so it causes you to urinate more frequently. Drinking caffeinated beverages will boost athletic performance but also elevates your risk of potential dehydration.
Beneficial Effect on High-Intensity Athletic Performance
A study featured in a 2005 issue of "Medicine and Science in Sports and Exercise" found that caffeine induced a 0.5 to 2.9 percent boost in the sprint speeds of rugby players. The study involved nine male rugby players who were divided into two groups. One group ingested caffeine and the other group took a placebo 70 minutes before undergoing a rugby test. The test itself consisted of seven circuits that included stations for measuring sprint time and power generation. The group that consumed caffeine displayed boosts in performance, as well as increased epinephrine levels. This suggests a correlation between heightened performance, caffeine and epinephrine. More tests are necessary to provide a clearer understanding of this purported correlation, however.
Caffeine and Blood Pressure
One potential adverse effect of caffeine is increased blood pressure. The caffeine content in 2 or 3 cups of coffee is enough to elevate your systolic blood pressure by 3 mmHg to 14 mmHg, and your diastolic blood pressure by 4 mmHg to 13 mmHg, MayoClinic.com says. This increase in blood pressure occurs regardless of whether or not you have hypertension. So people who regularly drink caffeinated beverages generally have higher blood pressure than people who do not. Athletes who regularly consume caffeinated energy drinks or sports drinks also increase their risk of developing high blood pressure, as well as long-term complications associated with hypertension.
Caffeine's Effect on Urine Production
The "International Journal of Sports Medicine" published a study in 1997 that found that 25 mg/dL of caffeine caused as much urine volume as 398 mL to 430 mL during exercise. The study examined the difference between the effects of caffeinated and non-caffeinated electrolyte drinks on urine volume. Urine volume was measured during 1 to 4 hours of rest followed by 3 hours of cycling in six test subjects. The study determined that the difference between consuming caffeinated and non-caffeinated drinks was not significant during moderate endurance exercise. However, because the study was limited to moderate endurance exercise, the same may not apply to high-intensity sports.
Overdose Side Effects
Consuming excessive caffeine sometimes causes breathing problems, confusion and diarrhea, MedlinePlus notes. Other side effects include dizziness, arrhythmia, insomnia and muscle twitching. Such side effects will interfere with your ability to perform at your peak athletic performance level.
References
- "International Journal of Sports Medicine"; Caffeine vs Caffeine-Free Sports Drinks: Effects on Urine Production at Rest and During Prolonged Exercise; R.C. Wemple, et al.; January 1997
- KidsHealth.org; Caffeine; Mary L. Gavin; January 2008
- Mayo Clinic; Caffeine; Sheldon G. Sheps; November 2009
- "Medicine and Science in Sports and Exercise"; Multiple Effects of Caffeine on Simulated High-Intensity Team-Sport Performance; G. R. Stuart, et al.; November 2005
- MedlinePlus; Caffeine Overdose; Jacob L. Heller; January 2010
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