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Energy Drinks: Potential Performance-Enhancers or Publicity Hype?

Jordan Levy

2/15/09

 

Introduction

Text Box: http://jeffsrivermart.com/store/image/2cbje/Energy_Drinks_Energy_Drinks.jpgDespite its relatively recent first sale in 1997, Red Bull energy drink has since become the world’s leading energy drink, selling over 100 billion cans annually in 100 different countries. (http://www.fundinguniverse.com/company-histories/Red-Bull-GmbH-Company-History.html). Its success sparked the invention of hundreds of other energy drinks, creating a market for a product that, despite its current popularity, was nonexistent not more than 10 years ago. Currently, more than 130 different types of energy drinks are sold in the United States, with names such as “Monster,” “Full Throttle,” “No Fear,” “Amp” and “Rockstar” that conjure images of extremeness, intensity, and power (http://www.csmonitor.com/2006/0607/p13s01-lifo.html). This is far from coincidental, as most energy drinks make valiant claims about the benefits of their product, competing with one another to create a description that conveys the most extreme kick of energy and best performance-enhancing results. For instance, the energy drink Cocaine is said to be a “legal alternative” to its illicit class A namesake, providing consumers with a kick of caffeine 350 times stronger than Red Bull (http://www.dailymail.co.uk/news/article-406304/Cocaine-drink-claims-real-thing.html), while Enviga “burns calories” and “gently boosts metabolism” (http://www.enviga.com/). Perhaps the most impressive claims are made by the world leader in energy drinks, Red Bull, which claims to “give you wings,” or more specifically states that it can “improve performance, especially during times of increased stress or strain, increase concentration and improve reaction speed, and stimulate the metabolism” (http://articles.latimes.com/2004/aug/23/health/he-energydrinks23). It’s clear that in the relatively new market for energy drinks, there is a great deal of competition and as a result, energy drink companies feel pressured to make impressive claims in order to sell more. Consequently, the question is raised regarding the veracity of these statements – what effect does Red Bull really have on performance, both mental and physical?

Text Box: =http://upload.wikimedia.org/wikipedia/commons/0/0f/Red_Bull_250mL_Can.jpgWhy do people consume energy drinks?

            There are two domains of the use of energy drinks – to improve mental performance and to improve physical performance. In terms of mental performance, the largest consumer of energy drinks is the population of college students, who often rely on heavily-caffeinated beverages to combat the effects of a lifestyle high in stress, studying and partying and low in adequate rest. In a survey by Malinauskas et al. (2007) of 496 randomly selected college students at a state university in the Central Atlantic region of the United States, 51% were found to be “energy drink users,” which is defined as having consumed at least one energy drink per month throughout the course of a semester. Of those students, 67% consumed Red Bull for insufficient sleep, 65% for increased energy, and 52% to drink with alcohol while partying.

            Many athletes use energy drinks to improve their athletic performance as well. Since it contains caffeine, a known performance-enhancer, many athletes turn to heavily-caffeinated beverages such as Red Bull for an energy boost prior to a competition. The Sports Medicine Institute of Manitoba reports that caffeine can especially benefit endurance athletes due to caffeine’s ability to consume fat as energy early on during exercise, leaving a greater concentration of muscle glycogen later on. Consequently, many athletes consume energy drinks to achieve these results.

What are the active ingredients in Red Bull and what effect do they have on the human body?

            Red Bull contains several ingredients that are known to have effects on human performance, including taurine, glucuronolactone, caffeine, B vitamins, and glucose (C. Alford et al., 2000).

         Taurine is an amino acid that affects the metabolism. It is an inhibitory neurotransmitter and has the ability to stabilize nerve cell membranes, making it a useful treatment for epilepsy and other excitable brain states (http://www.healthy.net/scr/article.asp?ID=1971). According to Garcia de Yebenes Prous et al. (1978), taurine also interferes with motor behavior and temperature regulation and inhibits firing on brain stem, spinal cord, and cerebral cortex neurons. Additionally, as reported by Alford et al. (2003), taurine is known to affect

mood (Mandel et al., 1985) as well as stress and behavior (Belfer et al., 1998; Milakofsky et al., 1993; Yamamoto et al., 1985).

Glucuronolactone is a naturally occurring metabolite formed from glucose in the liver (Finnegan, 2003). As reported by Alford et al., (2003), glucuronolactone can have an important effect on endurance athletes (Geiss et al., 1994). In the same study, it was also reported that although little is known about the effects of glucuronolactone on the human body, in endurance athletes it may provide additional energy resources (Hollmann, 1964). 

         Alford et al. (2000) reports that caffeine acts as an adenosine receptor blocker, which results in a stimulant effect. (Biaggoni et al., 1991; Franchetti et al., 1994; Fredholm, 1995; Le Blanc and Soucy, 1994). According to Fredhom et al. (1999), this can lead to effects on other neurotransmitters, which is what affects numerous physiological functions (Daly, 1993). Alford et al. (2000) also report that caffeine has not only been shown to improve performance on memory tasks (Barraclough and

Text Box: http://sparror.cubecinema.com/cube/cola/chemistry/figures/caffeine.gifText Box: Caffeine moleculeForeman, 1994; Davidson and Smith, 1991; Smith et al., 1994) but also can increase a variety of aspects of physical performance, such as endurance and peak muscle strength (Anselme et al., 1992; Berglund & Hemmingsson, 1982; Burke, 1992; Costill et al., 1978; Falk et al., 1990; Graham and Spriet, 1991; Lindinger et al., 1993; Meliska and Lawson, 1996; Spriet et al., 1992).

         Finally, B vitamins and glucose also have a number of beneficial effects on the human body. According to Alford et al. (2000), when glucose is metabolized it releases energy during both aerobic and anaerobic activity (Sizer and Whitney, 1997), and has also been suggested to improve cognitive performance, though results for this finding have been inconsistent (Azari, 1991; Benton and Owens, 1993). As for vitamin B12, consumption after depletion in the body may result in an increase in physical performance due to its energy production (McArdle et al, 1994).

Experimental Data

         With the rapid increase in popularity of energy drinks, as well as the boldness of many of their claims, a number of studies have since been performed to scientifically determine the effects of caffeine on both mental and physical performance.

         Perhaps the most conclusive results have been in the studies of the effect of energy drinks on physical performance, most likely because data can easily be obtained and analyzed to form a conclusion. However, there have been numerous studies on the mental aspect of performance as well that have yielded determinant results. In a series of studies conducted by Alford et al. (2000), the effects of energy drinks on both mental and physical performance were analyzed. The first study consisted of 5 male and 5 female subjects ages 18-30, with a mean age of 23 years. The second study consisted of 7 male and 7 female subjects, ages 18-35, with a mean age of 24 years. The third study consisted of 7 male and 5 female subjects, ages 20-21. These subjects were healthy, unpaid volunteers recruited from the University of the West of England in Bristol, UK and included moderate caffeine users. The various studies assessed heart rate, blood pressure, subjective mood, and choice-reaction time both before and after the treatment, aerobic endurance, performance on cognitive tasks, memory and concentration both before and after treatment, and anaerobic endurance.

         In the mental performance studies, subjects were given either carbonated mineral water or Red Bull energy drink. They then had to complete a series of tests, including a concentration test in which subjects had to eliminate a certain digit from a sheet of random characters so that the distribution of single digits was appropriately balanced, as well as a memory test, in which subjects were given one minute to memorize 22 two-digit numbers and then recall as many as they could. Heart rate, blood pressure, and both aerobic and anaerobic endurance were measured throughout. These test were double-blind and assessments were made before consumption, as well as thirty minutes after consumption of the beverage.

         In the physical performance studies portion of the same experiment, an initial measurement of aerobic threshold was taken prior to consumption. Then, after a 3 minute warm up period, the work rate increased until the subject was maintaining a 65-75% maximum heart rate. This level of work was maintained until the heart rate moved outside of these limits, with the elapsed time measuring aerobic endurance. To determine anaerobic endurance, a maximum effort cycling procedure was done with the length of time without slowing measuring anaerobic endurance.

         The results of these experiments showed that Red Bull improved choice reaction time, heart rate, subjective alertness, and both aerobic and anaerobic endurance. Compared to the consumption of no drink or carbonated water, Red Bull consistently had the highest human performance, with improvements in mental performance as well. According to the study, “the consistent improvements seen here may well reflect the physical and mental benefits of the combined ingredients in this energy drink." Thus, in the experiment by Alford et al. (2000), Red Bull had positive effects on both mental and physical performance.

Physical Performance

         Another experiment measuring the effects of energy drinks on physical performance found similar results. Geib et al. (1994) investigated the effect of a taurine-containing beverage, representing Red Bull, on endurance athletes. Ten male endurance athletes, with the mean age of 24.5 and who trained from 10-15 hours a week, were put on a regular diet and exercise plan for 3 weeks prior to the experiment. They would fast for 2 hours prior to each exercise session. Then, they would engage in a workout in which they cycled for 60 minutes at approximately 70% VO2 max on a cycle ergometer. After this, the workload on the ergometer would be increased every 3 minutes by 50 Watts until fatigue, which was defined as the point at which pedaling slowed to below 10% of the set rate due to fatigue. After 30 minutes of the initial 60 minute cycling, the athletes would be given one of three different beverages in a double-blind study– “Red Bull” with glucose, caffeine, and saccharose but without taurine and glucuronolactone,  “Red Bull” with glucose and saccharose but without taurine, glucuronolactone, or caffeine, or the original “Red Bull” containing taurine, glucuronolactone, caffeine, glucose, and saccharose.

         The results of this experiment demonstrated that physical performance was significantly greater among the athletes who consumed the original “Red Bull” beverage. Aerobic endurance increased by 9%, and anaerobic endurance increased by 24% in comparison to the control drinks, so as a result, there was a consistent and significant increase in physical performance among the endurance athletes in the study.

Cognitive Performance

         One final study pertaining to mental performance was conducted by Seidl et al. (2000). In it, 10 graduate students, 6 female and 4 male, ages 20-28 were selected for the experiment. Five of the students were non-caffeine users and five were regular caffeine users, defined as consuming at least one caffeinated beverage daily for at least a year. For 24 hours prior to each test session, each individual had to abstain from consuming caffeine. Then, after completing baseline measurements, participants would either consume 7 tablets containing the amount of caffeine, taurine, and glucuronolactone in a can of Red Bull or 7 placebo tablets. Then, after 60 minutes, the tests would commence. Subjects sat in a quiet, dimly lit room with their eyes closed and listened to a series of frequent and infrequent auditory stimulations. They were instructed to silently count all of the infrequent tones while ignoring the frequent tones, and then report the number they counted at the end of each session.

         Another test was also conducted which measured attention capacity in a stressful situation, as well as the status of an individual’s mood and state of wellbeing.

Text Box: http://www.rockwool.com/files/rockwool.com/Acoustics/Images/Performance.jpg         The results of these experiments concluded that after consumption of the tablet containing caffeine, taurine, and glucuronolactone, reaction time was significantly improved compared to the placebo tablets. Additionally, the caffeine, taurine, and glucuronolactone group experienced increased attention in a stressful situation and overall concentration compared to the placebo group. In terms of mood, the administration of a placebo pill caused a slight decline in feelings of wellbeing, whereas the caffeine, taurine, and glucuronolactone group experienced no decline in mood. Thus, the experiment concluded that the combination of caffeine, taurine, and glucuronolactone found in a can of Red Bull has beneficial effects on both cognitive performance and mood.

Are energy drinks worth the hype?

         Let’s revisit the claims made by Red Bull to see if the experimental data supports their validity or not. Red Bull claims it can “improve performance, especially during times of increased stress or strain, increase concentration and improve reaction speed, and stimulate the metabolism.”

         We know that Red Bull improves performance because in each of the three experiments described above, both mental and physical performance improved with the consumption of Red Bull or a drink containing the same active ingredients. Thus, this claim is true. The aspect of the claim that says “especially during times of increased stress or strain” is true as well, because in the Seidl et al. (1994) experiment, performance in cognitive tasks was measured in stressful situations, yet mental performance was still improved.

Text Box: http://frogsmoke.com/wp-content/uploads/2008/02/red bull.jpg         We also know that Red Bull increases concentration and improves reaction speed, as concluded in the experiment by Alford et al. (2000), in which both of the above qualities increased with the consumption of Red Bull.

         Finally, the last claim made by Red Bull, a “stimulated metabolism”, is also true, as caffeine is a known stimulant of the metabolism. There are also several active ingredients in Red Bull that have not been studied extensively, so it is also possible that they may have metabolism-stimulating properties themselves.

         Consequently, it becomes evident that although the claims made by Red Bull energy drink may seem bold, there is at least some truth in each of them. While drinking a can of Red Bull certainly will not give an individual the ability to memorize endless lists of information and concentrate effortlessly during times of stress, there is certainly no harm in its consumption. Red Bull might be of greater use to an elite athlete, for whom every legal performance enhancement should be taken advantage of. Considering that in one experiment, compared to a placebo, Red Bull increased aerobic performance by 9% and anaerobic performance by 24%, the physical performance benefits of Red Bull are significant enough that its consumption might be recommended for athletes prior to training and competition.

         In conclusion, for their relative low cost and benefits in physical performance, energy drinks are worth it for athletes looking to gain an edge on the competition. However, for a poor college student looking for a way to fuel all-night study sessions, there are cheaper caffeinated alternatives that will provide a similar energy boost. Certainly, though, considering that there is no harm in the consumption of energy drinks, and since they are proven to improve both mental and physical performance, why not take advantage of the performance-enhancing properties they have to offer?

 

 


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