Energy drinks are a fairly recent sport product phenomenon. These products are marketed to consumers on both sides of the boundary between that of the traditional nutritional supplements and the fluid replacements used by athletes. Energy drinks are also intended as a revitalizing source of instant energy to active people, particularly the college and university student demographic, throughout the world.
An energy drink is a product that is intended to increase powers of concentration and reduce the effects of fatigue. In recent years, many athletes have consumed energy drinks of various types for these reasons, especially when they seek a relatively mild stimulant to aid performance. A sports drink is one manufactured for athletic use, with the primary purpose being fluid and electrolyte replacement (particularly elements such as sodium and potassium), which are lost through perspiration and the excretion of urine. Sports drinks generally will include some sugars, in the form of carbohydrates.
Energy drinks are manufactured throughout the world; a broad variety of ingredients is employed. Virtually all energy drinks contain caffeine, either as a freestanding additive, or through other ingredients chosen for their natural caffeine content. These common sport drink ingredients are cola, various types of tea, coffee extracts, and guarana (a plant that is native to the Amazon basin). These materials are used either singly or in combination with one another in the manufacture of energy drinks.
A number of brands of energy drinks include extracts of ephedra, a plant whose leaves contain the stimulant ephedrine. Ginseng, a root that has been favored by herbalists for many centuries for its restorative properties, is also found in energy drink formulations.
Energy drinks typically contain between 10% and 13% sugar by volume. The amount of caffeine present in an 8-oz serving of an energy drink will range between 70 and 80 milligrams (mg) of caffeine; this is the approximate amount of caffeine that is commonly present in a 5-oz cup of strong coffee. Caffeine is a substance that has a different effect on each person. The amount of caffeine in an energy drink may have a pronounced effect on someone who consumes very little caffeine, and it may conversely produce a very modest effect on the system of one who habitually consumes large amounts of caffeine on a daily basis. If an athlete were to consume energy drinks on a regular basis as a source of stimulant, the athlete would likely notice that over time, greater amounts of the drink and its corresponding caffeine are required to produce the desired stimulation; the greater amounts of caffeine would also impact on the ability of the body to maintain an optimal fluid level, given the diuretic qualities of the substance.
In many respects, most energy drinks may be described as a more caffeinated, slightly sweeter form of soda pop. The labeling on an energy drink must be carefully examined to determine what is contained in the formulation. In addition to the primary ingredients of interest in energy drinks to the athlete (caffeine, ephedrine, sugars, and flavoring), other substances have been introduced to energy drinks that are of unknown long-term impact on consumers and athletes alike. One example is taurine, an amino acid that is a naturally occurring component of the body's digestive process. Taurine is stated to enhance the stimulant effects of caffeine, yet it has never been definitively scientifically established to work in this fashion, nor is it clear what other effects, positive or negative, such additives bring to these beverages.
Energy drinks are sometimes mixed with alcohol to create a perceived high-energy cocktail. There are also alcoholic beverages that contain caffeine or other additives to produce stimulation of the central nervous system. The combination of alcohol and caffeine or other stimulants will produce diuresis, the process that triggers the increased production of urine in the kidneys. The presence of a stimulant in an alcoholic beverage will tend to mask the otherwise progressive effects of intoxication by alcohol, concealing fatigue but not altering the physical effect of alcohol on the body. Consumers of these beverages will tend to become more dehydrated, thus causing increased blood pressure and heart rate.
Energy drinks are a generally poor choice as a substitute for a sport drink with regard to fluid replacement. Given its higher percentage by volume of sugar, the fluid component of the energy drink will be absorbed more slowly into the body. The caffeine and other likely stimulants will act as diuretics. Energy drinks are also a poor selection if the intention on the part of the consumer is to supplement the diet. The energy drink typically contains few, if any, proteins, fiber components to aid digestion, vitamins, or minerals. While the amount of caffeine in an energy drink is of the quantity that has been scientifically proven to both stimulate the central nervous system, as well as assist in the increased utilization of fat stores as energy in endurance sports, energy drinks are of limited benefit to an athlete.