Kandice Reed

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INTRODUCTION: Consuming energy drinks before exercising has become popular among young adults. Most people consume energy drinks to increase their exercise intensity and duration. Investigations have been performed to analyze the effects of the caffeine from various energy drinks on exercise performance. During maximal exercise performance, heart rate, Rate of Perceived Exertion, and systolic blood pressure increase linearly with exercise time and workload. Diastolic blood pressure generally, changes very little with increasing exercise intensity. PURPOSE: The purpose of this research study was to examine the effect that caffeine in an energy drink has on maximal exercise performance. METHODS: Five male, physically active college students (Age 24.4 ± 2.9 yrs; Weight 174.4 ± 24.9 lbs; Height 70.2 ±2.0 in) of the UTA Kinesiology department volunteered to participate in this study. Informed consent was obtained before any testing was performed. Subjects were asked to report to the Cardiovascular Research laboratory on two different days. Upon arrival, each subject put on a heart rate monitor and a blood pressure cuff was placed on his right arm. The subject’s resting heart rate and blood pressure were measured prior to consumption of the beverages. Then, they were given either 10 ounces of Monster Energy Drink (MED) or Lipton Diet Green Tea (LGT) with Citrus (placebo). The order of drink consumed was randomly assigned. After about 20 min, HR and BP were measured and the treadmill was started. Each subject underwent a maximal exercise test using the Bruce Protocol for increasing speed and elevation. During each treadmill test, the subject’s heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and rate of perceived exertion (RPE) with ratings from 6 (Rest) to 20 (maximal exercise), and time of exercise were recorded. The treadmill was slowed for recovery once maximal exertion had been reached. The alpha level for significance was set at p < 0.05. RESULTS: The maximal values: HR (MED: 191.4 ± 8.7; LGT: 187.6 ± 10.2), Time of exercise (MED: 14.9 ± 1.6; LGT: 14.9 ± 1.9), SBP (MED: 175.4 ± 14.8; LGT: 178.2 ±7.2), DBP (MED: 85.2 ± 3.8; LGT: 84.8 ± 4.1), and RPE (MED: 17.4 ± 1.1; LGT: 15.8 ± 2.6) were not significantly different between the Monster Energy Drink and Lipton Diet Green Tea with Citrus (p > 0.05). CONCLUSION: The results of this study indicate that caffeine from an energy drink did not affect maximal exercise performance. Previous investigations show a significant difference in time during treadmill exercising with consumption of an energy drink indicating further research is needed.


Kinesiology | Life Sciences

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