The Effects of "Rip It" Energy Drink on Physiological and Mental Tasks
Experiment proposed by:
Kimberly Smith (Principle Investigator) and David W. Pittman, Ph.D. (Supervisor)
The popularity and sales of energy drinks continue to increase as people adopt more responsibilities and schedules become more overloaded. Through marketing claims proposing to improve performance, concentration, and mental acuity, many people believe that energy drinks are a quick and easy way to boost energy levels and increase productivity.
The central energy-enhancing ingredient in most energy drinks is caffeine--the most widely and commonly consumed psychoactive substance in the world. Caffeine acts as a central nervous system and metabolic stimulant increasing alertness, wakefulness, focus, the speed and clarity of thought, and a general improvement in body coordination. Approximately 45 minutes is required for the body to completely absorb and distribute caffeine to all tissues and remains in the system for as long as 3-4 hours.
The particular energy drink used in this study was “Rip It”. A single can contains 200 mg of caffeine; this is nearly three times the amount of caffeine found in a cup of coffee and nearly eight times the amount found in a regular can of soda!! Other active ingredients known to produce heightened SNS activity include Taurine, Inositol, and Guarana. “Rip It” is marketed with claims conveying that its ingredients modulate the brain’s neurochemical reaction such that the positive effects of caffeine are enhanced while the side effects are reduced. Little research assessing the actual effects of "Rip It" versus potential placebo effects has been conducted. (A placebo effect can best be described as observed changes in one's performance as a result of a "power of suggestion" when an inert treatment is administered).
Based on the energy-enhancing assertions proposed by energy drinks, the following study investigated the physiological and psychological effects of “Rip It” energy drink. Given the CNS effects of caffeine and the high dosage of caffeine found in “Rip It”, it was hypothesized that consuming one serving of “Rip It” would increase general performance across all measures. It was also hypothesized that consuming one serving of a placebo energy drink would mildly enhance performance on all aforementioned tasks in comparison to the control drink but to the extent of “Rip It”.
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Subjects: Eight undergraduate students at Wofford College served as subjects for the experiment.
Equipment: The equipment used in this study was the Biopac EEG and EMG Systems (computer, hand dynameter, EEG cap, electrodes), "Rip It" energy drink, "Rip It"-placebo energy drink (cranberry pomegranate juice and 7-Up, the control drink (water), and the internet computer game “Simon”. The placebo energy was mixed such that the caloric and sugar content matched that of the "Rip It" energy drink, but contained no caffeine.
Protocol: Subjects were recruited on a volunteer basis with the incentive of winning a $25 Papa John’s gift card through a pooled drawing held on March 26 as well as extra credit as determined by the affiliated professor. The subjects were instructed to refrain from any caffeine-consumption while participating in the experiment. They were then randomly assigned to a specified order of the drink conditions. The drinks were pre-poured into plastic cups designated with the appropriate label (1: "Rip It", 2: placebo, 3: control). Each subject ingested one of the beverages and returned 45 minutes to an hour later for testing. This time lapse provided for the caffeine to circulate throughout the body and be fully absorbed by all of the body’s tissues. Two phases of the experiment were implemented for measurement: an EMG recording and an EEG recording. The first phase measured the physiological effects on muscle potentials (EMG). Electrodes were placed at the elbow and wrist. The tasks required the subject to squeeze a hand dynameter at maximum effort for as long as possible. These measurements of the individual's duration (stamina) and degree (strength) of exerted force were recorded for future data analysis. The second phase measured physiological effects on brain beta-wave activity (EEG). The experimenter fit the electrode cap snuggly on the subject's head with the electrodes positioned to measure left and right frontal lobe activity. This area of the brain functions in memory, concentration, and cognition. The subject played the memory game "Simon" for an allotment of 5 minutes. Five data points derived at the 1, 2, 3, 4, and 5 minute marks assessed reaction time and memory. The number of games and the player's score were recorded for future data analysis. This procedure was replicated across the different drink conditions with each subject committing to three consecutive days of testing. Results were discarded if the subject did not return for each of the three trials or if the allotted 45-60 minute time frame had expired before the subject could be assessed.
A with-in subjects Analysis of Variance was conducted to explore the impact of the beverage on muscle performance and brain activity. Six dependent (measured) variables were used: maximum force exerted, time to half muscle fatigue, time to full muscle fatigue, the sum of brain activity, average number of "Simon" games played, and the average score per game. The independent (manipulated) variable the drink consumed. An ANOVA is a type of statistical test that analyzes the results of the experiment (the differences between "Rip It", the placebo, and the control) to determine any significant effects or findings. The subjects were divided into three groups according to which beverage was consumed (Group 1: "Rip It", Group 2: placebo, Group 3: control).
EMG data analysis determined a statistically significant effect of half muscle fatigue (F(2, 21)=5.004, p<0.05) and full muscle fatigue (F(2, 21)=5.004, p<0.05) between the three drink conditions. Figure 1 displays the time period in seconds in which the subjects' muscles were halfway fatigued. Figure 2 illustrates the time period in seconds in which the subjects' muscles reached maximum fatigue; at this point the subjects could squeeze the dynameter no longer as the muscle was completely exerted. Post-hoc comparisons indicated that the average muscle fatigue time for "Rip It" was significantly different from the placebo and control drink (p<0.05); the average time-length to muscle fatigue is noted on the appropriate bar in Figures 1 and 2. "Rip It" prolonged full muscle endurance by an average of 67.15 seconds in comparison to the placebo and an average of 36.7 seconds in comparison to the control (see Figure 2). Rip It" prolonged the muscles' half-life by an average of 33.58 seconds in comparison to the placebo drink and an average of 18.35 seconds in comparison to the control (see Figure 1). As demonstrated in Figures 1 and 2, the placebo and control did not differ significantly from one another across conditions. Additionally, the amount of force exerted was not found to be statistically significant.
EEG measurements reflect the sum of brain activity under the integrated signal. The integrated signal is the amount of increased and decreased brain activity variance. EEG data analysis determined a statistically significant interaction between hemisphere and measurement (F(4, 84)=2.714, p<0.05), such that 4 of the 5 measurements of beta-waves/brain activity for each subject was varied significantly between the left and right hemispheres. The particular drink ingested had no significant effects on left and right hemisphere activity. The average number of games and average score on the "Simon" memory task was not found to be statistically significant across the three drinks. Post-hoc comparisons indicated no significant differences between groups in relation to measurements although there was an interaction.
As demonstrated by EMG analysis and illustrated through Figures 1 and 2 , "Rip It" lessened muscle fatigue. The amount of time elapsed from task initiation to half-muscle fatigue to complete muscle fatigue was prolonged when the subjects consumed "Rip It"; they were able to prolong the amount of time in which they squeezed the dynameter at maximum force effort in comparison to the placebo drink and the control. However, the amount of force (strength) exerted was not different between the groups. This suggests that "Rip It" can prolong one's stamina/amount of time in which one can engage in physical activities but can not enhance strength/make one stronger.
As demonstrated by EEG analysis, although there was a difference in the degree of activity measured in the left versus right hemispheres, no difference was observed in the measurements recorded after the ingestion of each of the drink conditions. Therefore, the enhanced cognitive, attention, and concentration effects proposed by the media was not supported by this study's findings; all three of the drinks elicited the same response across the 5 minute-measurements in both the left and right hemisphere. A lack of difference in the number of games played and the average score per game suggests that "Rip It" and the placebo drink did not increase memory or reaction time during the Simon task.
For instances in which no significant results were found, it can be suggested that outside factors may have produced confounds in the study. While it was strongly suggested that individuals refrain from any type of caffeine ingestion, some students admitted to consuming coke products, coffee, and tea prior to assessment; this should be more tightly controlled in future experiments. Some subjects performed the experiment in the morning versus at night, after having a night's restful sleep versus no sleep, pre-/post exam versus having no exam, etc. All of these different testing conditions have effects that have been scientifically based to be either beneficial or deleterious to both the mind and body. While some subjects were being tested, distractions form outside of the room (talking, thunder storm, etc) and inside the room (cell phones ringing) most likely confounded brain activity measurements during the "Simon" task.
Note from the Primary Investigator
This experiment was conducted for both a learning exercise and a requirement for the Psychology 330 Behavioral Neuroscience class. I am a senior psychology major completing my concentration in neuroscience. This has been my first approach to human research as my primary experience focuses on behavioral and electrophysiological assessments of rats. As in animal research, the involved techniques and measurements require much fore-thought, patience, and organization, while unexpected surprises (from technological malfunctions to human forgetfulness and error) are inevitable. For example, during the recording stage of my experiment, we experienced a couple power-outages which delayed data-completion. Additionally, I experienced a "computer malfunction" which required me to re-record five of my eight subjects' data. Despite these minor inconveniences, creating and conducting an independent experiment has fostered in me a deeper appreciation for science and scientific research. I was able to explore activities in which I partake, such as ingesting large quantities of caffeine, and actually quantify their effects with scientific merit. So thank you to all who participated, and if you have any questions about this study, please e-mail me at firstname.lastname@example.org.