Energy
drinks typically contain water, carbohydrates, vitamins, minerals, with the aim
of increasing energy, alertness, metabolism, and/or performance (e.g.,
caffeine, taurine, amino acids, glucoronolactone...) (1).
Caffeine is the most common
ingredient, and is absorbed in 30-60 minutes (2). Caffeine stimulates
the cardiovascular system and increases epinephrine output (3,4); enhance vigilance during
bouts of exhaustive exercise, and periods of sustained sleep deprivation.
Energy
drinks with approximately 2 mg·kgBM-1caffeine consumed 10 to 60 minutes prior to anaerobic/resistance
exercise may improve
upper- and lower- body total lifting volume, and improve
cycling and running performance (1).
Carbohydrate feeding
during exercise can improve endurance
capacity and performance
(5,6), through maintenance of blood glucose levels, high levels of carbohydrate
oxidation (1 g of carbohydrate per minute), while sparing liver and skeletal
muscle glycogen (7).
Energy
drinks also have a small amount of vitamins (e.g., Vitamin B6, Vitamin B12,
pantothenic acid, Vitamin C) and electrolytes (e.g., sodium, potassium,
phosphorus, etc.).
Energy
drinks can improve mood, reaction time, and/or markers of alertness,
most likely due to the ergogenic value of caffeine and/or carbohydrate.
Caffeine
can elevate metabolic rate and the rate of lipolysis. 200-500 mg of caffeine (typical of
thermogenic supplements) can increase acute energy expenditure (1-24 hours)
(1), chronic energy expenditure (28 days) (8), and elevate plasma free-fatty
acid, glycerol levels and catecholamine secretion (1,8). The caffeine in energy
drinks ranges from 80-200 mg, and it’s not conclusive whether daily use of ED
would affect long-term energy balance and body composition (1).
Individuals
with metabolic
syndrome and or diabetes mellitus
should avoid
consumption of high glycemic drinks and/or foods. More importantly, individuals
with known cardiovascular
disease should avoid any use of energy drinks due to the cardiostimulant
effects (1).
It is wise
not to consume energy drinks more than one serving per day, indiscriminate
consumption may lead to adverse events and harmful side effects.
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References:
1. Bill Campbell, Colin Wilborn,
Paul La Bounty, Lem Taylor, Mike T Nelson, Mike Greenwood, Tim N Ziegenfuss,
Hector L Lopez, Jay R Hoffman, Jeffrey R Stout, Stephen Schmitz, Rick Collins,
Doug S Kalman, Jose Antonio and Richard B Kreider. International Society of
Sports Nutrition position stand: energy drinks. Journal of the International Society of Sports
Nutrition 2013, 10:1
2. Goldstein ER, Ziegenfuss T,
Kalman D, Kreider R, Campbell B, Wilborn C, Taylor L, Willoughby D, Stout J,
Graves BS, et al: International society of sports nutrition position stand:
caffeine and performance. J Int Soc Sports Nutr 2010, 7:5.
3. Graham TE, Hibbert E, Sathasivam
P: Metabolic and exercise endurance effects of coffee and caffeine ingestion. J
Appl Physiol 1998, 85:883–889.
4. McLellan TM, Bell DG: The impact
of prior coffee consumption on the subsequent ergogenic effect of anhydrous
caffeine. Int J Sport Nutr Exerc Metab 2004, 14:698–708.
5. Jeukendrup A, Brouns F,
Wagenmakers AJ, Saris WH: Carbohydrate-electrolyte feedings improve 1 h time
trial cycling performance. Int J Sports Med 1997, 18:125–129.
6. Jeukendrup AE: Carbohydrate
intake during exercise and performance. Nutrition 2004, 20:669–677.
7. Coyle EF, Coggan AR, Hemmert MK,
Ivy JL: Muscle glycogen utilization during prolonged strenuous exercise when
fed carbohydrate. J Appl Physiol 1986, 61:165–172.
8. Roberts MD, Dalbo VJ, Hassell SE,
Stout JR, Kerksick CM: Efficacy and safety of a popular thermogenic drink after
28 days of ingestion. J Int Soc Sports Nutr 2008, 5:19.
