Evaluation of Energy Drink Consumption on ECG and Hemodynamic Parameters in Young Healthy Volunteers

Inclusion Criteria: * Healthy male and female, active duty military service members or DoD beneficiaries, who are eligible to receive care at DGMC. * Ages 18-40 years old * Participants must be willing to refrain from caffeine and energy drink use 48 hours prior to study days 1 and 8. They must also refrain from consuming additional caffeine or energy drinks during the 24-hour observation time on days 1-2 and 8-9. Exclusion Criteria: * Cardiovascular risk factors: Heart rhythm other than normal sinus, history of atrial or ventricular arrhythmia, family history of premature sudden cardiac death before the age of 60, left ventricular hypertrophy, atherosclerosis, hypertension, palpitations, T-wave abnormalities, baseline corrected QT (QTc) interval greater than 440 milliseconds(ms). This will be determined on the ECG obtained during initial screening appointment, and reviewed by cardiologist and through the questionnaire responses of the participant. * Blood pressure at initial screening appointment or at baseline on study Day 1 greater than 140/90 * Presence of any known medical condition, confirmed through participant interview. Examples of these are: * Hypertension * Thyroid disease * Type 1 or 2 diabetes mellitus * Recurrent headaches * Depression, currently receiving treatment (due to possible drug interactions) * Any psychiatric condition or neurological disorder * History of alcohol or drug abuse in the previous 5 years * Ever been diagnosed or told they have or had renal or hepatic dysfunction * Concurrent use of ANY medication taken on a daily basis, to include herbal products or supplements. Daily basis is defined as greater than 2 days per week. * Pregnant or lactating females will be excluded from participation with urine dipstick tests used to confirm pregnancy (pregnancy test performed before each treatment session, days 1 and 8) * All non-English speaking / writing subjects and those that do not understand the study or consent process will be excluded from the study due to unavailability of medical qualified translator at all times during the study. * If the subject refuses to sign the informed consent document or HIPAA Authorization, they will be excluded as well