Energy Drinks: A review

According to published research, energy drinks are the most popular dietary supplement in American adolescents and young adults, secondary only to multivitamins (1), and are also reported to be the most popular supplement amongst British athletes (2).

The term ‘energy drink’ is used loosely, and often interchangeably with regard to describing ‘energy drinks’, ‘energy shots’, and/or ‘sports drinks’, yet, there are distinct differences between these items which are important to highlight.

|Sports Drinks:

Sports drinks are unique in their marketed audience (athletes, exercisers, and all-round on the goers!) and primarily promote optimal hydration, electrolyte replacement, and sustaining endurance performance. They typically provide smaller doses of carbohydrates (compared to energy shots & energy drinks) of ~6-8g/100ml and essential electrolytes such as sodium, calcium, potassium, and magnesium.

|Energy Drinks:

Energy drinks typically contain much higher carbohydrate values (25-30g/240ml) than sports drinks, and generally contain nutrients purported to increase perceptions of attention and/or mental alertness (3). Energy drinks are marketed to athletes, however, due to their potential benefits in mental alertness they are also directed towards, students, business people, and late-night workers.

|Energy Shots:

Energy shots are pretty much what they say on the can, a shot. Typically, shots are ~2-4oz servings of concentrated energy drinks, and like their big brother they usually contain carbohydrate, caffeine, and various mixtures of purported ergogens such as taurine, glucuronolactone, Ginkgo biloba, Ginseng, Green Tea, and/or Yerba Mate (for example) which may increase energy, mental focus, alertness, concentration, and/or metabolism so consequently, have the potential to affect exercise capacity and perceptions of fatigue (3).

|Exercise Performance:

During the last few years there has been a great deal of research conducted looking at the effects of energy drinks on several types of exercise, including resistance training, high intensity anaerobic exercise, speed & agility sessions, and aerobic/endurance exercise.

Conclusions, with regards to anaerobic resistance training suggest that energy drinks containing 2mg/kg.BW-1 caffeine consumed ~45-60 minutes prior to exercise may improve upper and lower body total lifting volume (4), yet, has no effect on repeated high intensity speed/agility performance (5).

Several studies have investigated the effects of energy drinks prior to commencing endurance exercise, and concluded that energy drinks containing ~2mg/kg.BW-1 caffeine consumed 10-40 minutes before aerobic exercise improves cycling and running performance in both trained, and recreational athletes. However, the evidence would also suggest that taking this kind of energy drink ~60 minutes prior to aerobic exercise may be too long of a period to have a noticeable performance outcome (6).

Sports drinks, such as Mountain Fuel Xtreme Energy are manufactured and marketed for athletes and consequently, are used during high-intensity exercise and/or prolonged bouts of exercise (>45-60 minutes).

|Mental Performance:

There currently seems to be a consensus among research studies which suggests that energy drinks do improve mood, reaction time, mental focus, and alertness, primarily through their caffeine and/or carbohydrate content. Consequently, individuals who wish to increase any of the above mental focus variables may benefit from the consumption of an energy drink prior to exercise and/or competition.

There are also potential benefits to consuming an energy drink late in to some ultra-endurance events to aid in mental alertness, concentration, and the battle with fatigue.

|Related Weight & Health Considerations:

With regards to weight-loss/gain, there has been reports of low calorie energy drink intake increasing resting energy expenditure and fat metabolism on an acute basis (3). There have also been preliminary studies which have reported positive body composition adaptations to pre-exercise energy drink and/or thermogenic drink consumption. Yet, it is important to add that daily consumption of higher calorie energy drinks may promote unwanted weight-gain.

Several energy drinks are manufactured with up to 50g of simple sugars, and therefore the consumption of these types of beverages prior to exercise are potentially going to increase insulin levels in order to maintain optimal blood glucose. It is for this reason that diabetics, pre-diabetics, and those individuals with any kind of metabolic syndrome should avoid consuming high glycemic load energy drinks, and chose a lower calorie version energy drink if one has to be consumed (7,8).

|References:

1– Froiland K, Koszewski W, Hingst J and Kopecky L. Nutritional Supplement Use Among College Athletes and their Sources of Information. Int. J. Sport Nutr. Exerc. Metab. 14:104-120, (2004)

2– Petroczi A. Naughton DP, Pearce G, Bailey R, Bloodworth A and McNamee M. Nutritonal Supplement use by Elite Young UK Athletes: Fallacies of Advice regarding Efficacy. J. Int. Soc. Sports Nutr. 5:22, (2008)

3– Campbell B, Wilborn C, Bounty PL, Taylor L, Nelson MT, Greenwood M, Ziegenfuss TN, Lopez HL, Hoffman JR, Stout JR, Schmitz S, Collins R, Kalman DS, Antonio J, and Krieder RB. International Society of Sports Nutrition position stand: Energy Drinks. JISSN, 10:1 (2013)

4– Del Coso J, Salinero JJ, Gonzalez-Millan C, Abian-Vicen J, and Perez-Gonzalez B. Dose Response Effects of a Caffeine-Containing Energy Drink on Muscle Performance: A Repeated Measures Design. J. Int. Soc. Sports Nutr. 9:21, (2012)

5– Astorino TA, Matera AJ, Basinger J, Evans M, Schrman T, and Marquez R. Effects of Redbull Energy Drink on Repeated Sprint Performance in Woman Athletes. Amino Acids, 42:1803-1808, (2012)

6– Candow DG, Kleisinger AK, Grenier S, and Dorsch KD. Effect of Sugar-Free Redbull Energy drink on High-Intensity Run Time-to Exhaustion in Young Adults. J. Strength Cond. Res. 23:1271-1275, (2009)

7– Sepkowitz KA. Energy Drinks and Caffeine-Related Adverse Effects. JAMA. 1-2 [Epub ahead of print] (2012)

8– Torpy JM and Livingston EH. Energy Drinks. JAMA. 1-1 [Epub ahead of print] (2012)