Caffeine-Loaded Energy Drink Increases Blood Pressure
Researchers have documented a statistically significant increase in blood pressure and catecholamines in a group of young healthy adults who consumed one can of a commercially available energy drink (Rockstar, Rockstar Inc).
In a small study of just 25 volunteers, researchers, including lead investigator Dr Anna Svatikova (Mayo Clinic, Rochester, MN), measured multiple variables 30 minutes after subjects drank the popular beverage. Consuming one 480-mL can of Rockstar energy drink, which contains 240 mg of caffeine, increased systolic blood pressure 6.2%, up from 108.4 mm Hg at baseline to 115.0 mm Hg. Consumption of a placebo beverage resulted in a 3.1% increase in systolic blood pressure, up from 108.3 mm Hg to 111.6 mm Hg. The differential blood-pressure response in this randomized, double-blind, crossover pilot study was statistically significant.
In the placebo arm, diastolic blood pressure was unchanged, whereas researchers documented a 6.8% increase in volunteers after they drank Rockstar. Mean blood pressure increased from 74.2 mm Hg to 78.9 mm Hg after drinking the energy drink, a 6.4% increase, but only increased 1.0% after drinking the placebo. Again, this difference was statistically significant.
"Physical, mental, or cold stress did not further accentuate the blood-pressure increase," report Svatikova and colleagues.
Although heart rate was unaffected by the energy drink, mean norepinephrine levels were significantly affected. After subjects drank Rockstar, mean norepinephrine levels increased 73.6% vs 30.9% after drinking the placebo.
The researchers concede the study was small and only one energy drink was tested but suggest the acute hemodynamic and adrenergic changes "may predispose [individuals] to increased cardiovascular risk." Larger studies are needed, however, to determine whether the acute response translates into a significant hazard.