Sports drinks, also known as electrolyte drinks, are functional beverages whose stated purpose is to help athletes replace water, electrolytes, and energy before, during and especially after training or competition. The evidence is lacking pertaining to the efficacy of use of commercial sports drinks for sports and fitness performance.[1]
Consuming too much or in unnecessary circumstances may hinder health or performance. The drinks, or some of their ingredients such as sugar, may not be suitable for certain conditions.[1]
Sports drinks can be split into three major types:[2]
Isotonic sport drinks contain similar concentrations of salt and sugar as in the human body.
Hypertonic sport drinks contain a higher concentration of salt and sugar than the human body.
Hypotonic sport drinks contain a lower concentration of salt and sugar than the human body.
Most sports drinks are approximately isotonic, having between 4 and 5 heaped teaspoons of sugar per eight ounce (13 and 19 grams per 250ml) serving.[3]
Athletes that are actively training lose water and electrolytes from their bodies by sweating, and expending energy. Sports drinks are sometimes chosen to be a solution for this problem through fluid replacement, carbohydrate loading and nutrient supplementation,[4] although the same source also states that “Whether water or a sports drink is consumed is the athlete's choice.”.[5]
Studies show that, contrary to popular belief, the consumption of an electrolyte-containing sports drink does not protect against hyponatremia (low sodium in the blood). This is likely due to the fact that the sodium content of these drinks is in the range of 20 to 30 meq/L.[6]
A stated purpose of sports drinks, which provide many calories of energy from sugars, is to improve performance and endurance. The potential benefits of sports drinks depends upon other factors including the quantity of the beverage ingested, the time it takes for the drink to be emptied from ones body, absorption time, and the carbohydrate type,[7] although the same source states that “there is little evidence that any one sports drink is superior to any of the other beverages on the market.”.[8]
A 2019 meta-review found that “dairy milk may provide either comparable or superior recovery nutrition qualities with regards to muscle protein synthesis, glycogen replenishment, rehydration, and subsequent endurance exercise performance, when compared to non-nutritive, carbohydrate replacement, and (or) carbohydrate-electrolyte alternatives.”.[9]
Some potentially harmful health effects of drinking sports drinks without prolonged exercise include weight gain, diabetes and dental erosion.[10][11][12] These drinks are high in calories and sugar which thereby can contribute towards an unhealthy diet.[13] Generally, commercial sports drinks contain two-thirds the amount of sugar found in a normal soda. The sugar found in these sports drinks still exceeds the recommended amount of sugar in a day for a child.[14]
Energy drinks, which are often confused with sports drinks, usually contain high amount of caffeine among other dietary supplements. Often the concentration of caffeine is higher than found in soft drinks.[15] In moderate amounts, caffeine is not harmful and can provide various benefits regarding endurance; however, in large amounts this can have adverse effects.[16] Although energy drinks may contain various different dietary supplements, health studies have claimed that there is a lack of thorough labelling which means that consumers may not always be aware of what they are consuming.[15]
In the 19th and early 20th centuries, athletes occasionally drank beer of low alcohol content to replenish water, minerals and energy in the body. As the water is boiled during the brewing process and thus sterilized, the beer was a safer option than water from an unknown source.[17] However, studies suggest that even a low dose of ethanol decreases endurance performance: it inhibits liver glucose output during exercise, and also impairs psychomotor skills such as reaction time, hand-eye coordination and balance.[18]
Since the first modern Olympics, fluid intake during sports have been much varied due to a lack of consensus in the scientific community pertaining to the use of sports drinks. In the early 1900s there was a widespread belief that consumption of fluids such as water during exercise was unnecessary.[19] However, with the advancement of exercise physiology in 1923, the cardiovascular model of thermoregulation was researched by A.V. Hill.[19] Based on this model, the consequences of water loss and the significance of fluid consumption was emphasized.[19]
Energy drinks and sports drinks first appeared in Europe and Asia in the 1960s as a response to demands for dietary supplements that would increase energy. Taisho Pharmaceuticals, a Japanese company, introduced Lipovitan D, one of the first energy drinks on the market in 1961.[20] Since then, both energy drink and sports drinks have developed into a multibillion-dollar market.
The sports and energy drinks market is rapidly growing around the world. Sports drinks are included within the functional drinks market. Within the functional drinks category, sports and energy drinks account for the largest volume growth.[20] These drinks have experienced exponential growth of more than 240% in the United States of America and around the world from the years 2004 to 2009.[20]
There have been a variety of different types of drinks introduced to the market over the years, many of which target young athletes.[21]
^Russo, Isabella, et al. "Systematic literature review: The effect of dairy milk on markers of recovery optimisation in response to endurance exercise." International Journal of Sports Science (2019): 69-85.
