1. Statement of the research question:

   Does the caffeine in energy drinks interact with other ingredients to affect cardiovascular function in healthy male and female adults after exercise?

2. Purpose and significance of the study:

Energy drinks are beverages promoted to enhance alertness along with athletic and cognitive performance. The most common ingredients found in energy drinks include water, sugar, caffeine, taurine, and B-vitamins, with variable inclusion of other ingredients, such as carnitine, glucuronolactone, inositol, guarana, ginkgo biloba leaf extract, thistle extract, and ginseng root extract. Since the mid-1990s, the consumption of energy drinks has grown dramatically, with worldwide sales in 2017 exceeding $49 billion.

As the sale of energy drinks has grown, so has the number of adverse event case reports for patients who consumed energy drinks. Reported symptoms included cardiac arrhythmias such as ventricular fibrillation, atrial fibrillation, and cardiac arrest. A few small clinical studies have found that energy drinks can increase systolic and diastolic blood pressure and change electrical activity in the heart as measured by an electrocardiogram (ECG). The intent of the proposed study is to determine whether caffeine or the combination of caffeine with taurine and L-carnitine can alter cardiovascular function. Hypothesis: The effects of the ingredients of energy drinks on the heart are mediated in part by interactions between caffeine, taurine and carnitine. The amount of each ingredient in the study was based upon the amount commonly contained in two cans of energy drinks currently on the market.

Title: The Effect of Energy Drink Ingredients on Cardiovascular Function

1. Statement of the research question

   Does the caffeine in energy drinks interact with other ingredients to affect cardiovascular function, including QTc interval of the EKG, heart rate and blood pressure in healthy male and female adults after exercise?

2. Purpose and significance of the study

Energy drinks are beverages promoted to enhance alertness along with athletic and cognitive performance. The most common ingredients found in energy drinks include water, sugar, caffeine, taurine, and B-vitamins, with variable inclusion of other ingredients, such as carnitine, glucuronolactone, inositol, guarana, ginkgo biloba leaf extract, thistle extract, and ginseng root extract. Since the mid-1990s, the consumption of energy drinks has grown dramatically, with worldwide sales in 2017 exceeding $49 billion.

As the sale of energy drinks has grown, so has the number of adverse event case reports for patients who consumed energy drinks. Reported symptoms include cardiac arrhythmias such as ventricular fibrillation, atrial fibrillation, and cardiac arrest. A few small clinical studies have reported that energy drinks can increase systolic and diastolic blood pressure and change electrical activity in the heart as measured by an electrocardiogram (EKG). The intent of the proposed study is to determine whether caffeine or the combination of caffeine with taurine and L-carnitine can alter heart rate, blood pressure and the QTc interval of the EKG. Caffeine stimulates cardiovascular function primarily through antagonism of adenosine receptors. Taurine is a modulator of intracellular calcium ion concentrations which can affect the strength cardiac contraction. Carnitine facilitates fatty acid transport into the mitochondria, thereby increasing the production of adenosine triphosphate, the energy source of cells. Hypothesis: the effects of the ingredients of energy drinks on the heart are mediated in part by interactions between caffeine, taurine and carnitine. The amount of each ingredient in the study was based upon the amount commonly contained in two cans of energy drinks currently on the market.

Inclusion Criteria:

1. No preexisting medical conditions (including pregnancy)
2. Subjects must be capable of exercising on a treadmill (Vigorous activity: more than 7 kcal/min; https://www.cdc.gov/nccdphp/dnpa/physical/pdf/PA\_Intensity\_table\_2\_1.pdf)
3. BMI within normal range (18.5 - 24.9 kg/m2)
4. Average daily caffeine intake between 1 and 5 caffeinated beverages

Exclusion Criteria:

1. Age below 18 or greater than 39 years
2. Unable to provide legal consent to participate in the study
3. Preexisting medical conditions including but not limited to: pregnancy, cardiovascular disease, endocrine disorders, psychiatric or neurological disorders, musculo-skeletal disorders, immune disorders, respiratory disorders, dermatological disorders, infections, blindness, hearing disabilities
4. BMI less than 18.5 or greater than 24.9 kg/m25.
5. Current or future students of Drs. Johnson and/or Montepara
6. Incarceration in local, state or federal justice systems

The three test solutions will be coded as "A", "B" and "C". Both the subject and the provider of the test solution to the subject will be blinded to the ingredients in the solution. The person who provides the test solution will be blind to the identity of the subject other than by subject number. The person who analyzes the data will be blinded to subject identity and which test solution was administered. The key for the test solutions and subject identity will be kept in a locked drawer in the office of the principal investigator.