Post-Exercise Cardiovascular Responses Following Energy Drink Consumption
Condition: QTc Interval
Study type: Interventional

Summary: 
      The purpose of this study is to determine the effects of consuming an original flavor energy
      drink on electrocardiographic (ECG) and hemodynamic responses during and after exercise in
      healthy subjects. The effect of drinking an energy drink on exercise performance will also be
      evaluated.
    

Detailed description: 
      The study will employ a double-blinded, randomized, crossover design to evaluate the
      cardiovascular (CV) effects of an energy drink during post-exercise recovery. Subjects who
      express interest in the study will be screen for eligibility. Those who are eligible will be
      consented. An inquire into usual caffeine intake to assess caffeine naïve or caffeine
      tolerant. Participants height, weight and race will be recorded. A resting 12-lead baseline
      ECG and blood pressure (BP) will be obtained to rule out CV anomalies. A cardiologist will
      review every baseline ECG and BP reading to rule out everything but a normal sinus rhythm and
      BP < 130/80 mmHg. Subjects who meet inclusion criteria and are approved by the cardiologist
      will be enrolled and allocated a randomized participant identification (ID) number. They will
      be given the "Participant Instruction Sheet"

      Participants will be randomly assigned, blinded to consume a single 24 oz container of an
      energy drink or a 24 oz container of a control drink. Participants will serve as their own
      controls, so they will undergo testing in the experimental and control drink conditions,
      separated by 4 to 14 day. Each 24 oz control drink will be comprised of 585 ml of carbonated
      water, 30 ml of reconstituted lime juice and 105 ml of cherry flavoring. This control drink
      formula is identical to that used by Fletcher et al. (2017). The carbohydrate content of the
      24 oz control drink is 81 g, which is the same as the 81 g per 24 oz energy drink.
      Participants will fast 12 hours, asked to refrain from vigorous exercised 24-hours, and
      abstain from caffeine consumption 48-hours prior to consuming a randomly assigned single 24
      oz can of an original flavor energy drink within a 30-minute period. Investigator and
      participant will be blinded.

      Subjects will be asked to visit either Heart, Lung and Vascular clinic or exercised
      physiology laboratory (CSUS subjects) twice, separated by 4-14 days to undergo testing. ECG
      electrodes will be placed on the upper torso and remain in place throughout the experiment.
      Baseline ECG, HR, BP, blood sample and body weight will be obtained. Catheter placement and
      blood draws will be performed by a registered clinical cardiopulmonary technician, registered
      nurse or a resident physician. Approximately 20 mil of blood will be taken at each time
      point.

      Subjects will perform a continuous, progressive treadmill or bicycle ergometry test until
      volitional exhaustion. The treadmill test will begin with walking at 3.4 mph at 0% grade,
      then speed increased to 7 mph (males) or 6 mph (females) and grade increased by 2.5% every 2
      minutes until > 85% ag-predicted maximum heart rate and volitional exhaustion has been
      reached. Subjects performing the ergometry test will being cycling at a resistance of 100 W
      for 2 minutes with the resistance increased by 25 W (males) or 15 W (females), each minute
      thereafter. Maximum HR will be calculated using the Tanaka formula (Tanaka et al., 2001). A
      12-lead ECG will remain in place on subject and monitored continuously during exercise, and
      rating of perceived exertion (RPE) will be recorded every minute of each workload increase.
      After completion of exercise, subject will remain standing on treadmill (or seated on
      ergometer) for 10 minutes while ECG, BP, HR and blood samples are obtained. Subsequent ECG
      measures will be obtained at 1,4,7 and 10 minutes. After 10 minutes, the subjects will be
      free to sit, stand or move quietly in the lab. During the 2-hour post exercise monitoring
      period, subject's ECG, HR, BP will be recorded at 30-minute intervals. Blood samples for
      caffeine, taurine, L-carnitine, plasma free fatty acids, glucose and lactate will be
      collected immediate upon cessation of exercise, at 1 and 2 hours post exercise.
    

Intervention name(s): Energy Drink; Placebo-control
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Participants will consume a randomly assigned single 24 oz can of an original flavor energy drink within a 30-minute period. Baseline ECG, HR, BP, blood sample and body weight will be obtained. Then perform a continuous, progressive treadmill or bicycle ergometry test until volitional exhaustion. ECG will be monitored continuously during exercise, rating of perceived exertion (RPE) will be recorded every minute of each workload increase. After completion of exercise, subject will remain standing on treadmill (or seated on ergometer) for 10 minutes while ECG, BP, HR and blood samples are obtained. Subsequent ECG measures will be obtained at 1,4,7 and 10 minutes. After 10 minutes, the subjects will be free to sit, stand or move quietly in the lab. During the 2-hour post exercise monitoring period, subject's ECG, HR, BP will be recorded at 30-minute intervals. Blood samples will be collected immediate upon cessation of exercise, at 1 and 2 hours post exercise; Participants will consume a randomly assigned single 24 oz can of control drink within a 30-minute period. Baseline ECG, HR, BP, blood sample and body weight will be obtained. Then perform a continuous, progressive treadmill or bicycle ergometry test until volitional exhaustion. ECG will be monitored continuously during exercise, rating of perceived exertion (RPE) will be recorded every minute of each workload increase. After completion of exercise, subject will remain standing on treadmill (or seated on ergometer) for 10 minutes while ECG, BP, HR and blood samples are obtained. Subsequent ECG measures will be obtained at 1,4,7 and 10 minutes. After 10 minutes, the subjects will be free to sit, stand or move quietly in the lab. During the 2-hour post exercise monitoring period, subject's ECG, HR, BP will be recorded at 30-minute intervals. Blood samples will be collected immediate upon cessation of exercise, at 1 and 2 hours post exercise
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Health Services Research