According to a study by the Wayne State Undergraduate Research Fund, energy drinks can raise blood pressure. This may impact those with hypertension, cardiovascular disease, or those who are taking medication to lower blood pressure. The study also found that energy drinks that equal two cups of coffee may also effect young healthy people.
Consumption of two energy drinks a day increased systolic blood pressure by 10 mm Hg and heart rate by five to seven beats per minute, according to a small study reported at the American Heart Association meeting.
Energy drinks not only contain caffeine but they also contain the amino acid taurine. In other studies this has been show to affect cardiac function and hemodynamic status. However, caffeine studies have been controversial.
For more information on this subject, please refer to the section on Defective and Dangerous Products.