Sports Drinks

From Chempedia

Charles Volk
Raja Khalid
Nathan Bieber
Jake Biedrzycki

Sports Drinks

Sports Drinks are commercially made beverages that are basically solutions of water, sugar (carbohydrates) and salts (electrolytes). They were designed to replenish the bodily fluids lost during exertion and closely mimic the body’s fluids. Such solutions are called isotonic. Sports drinks are not a purely modern phenomenon. The first sports drink was Lucozade first manufactured in 1927 (Wikipedia, Sports Drink).

Sports Drinks are used today almost everywhere. They have even come out of the mainstream, athletic market, and are now used commonly in non-sporting venues as merely a cold drink. Though, due to the high amount of sugars in these products, they are not entirely recommended for daily consumption due to the promotion of tooth cavities.

Composition of Sports Drinks

Sports drinks are a homogeneous solution of many different ingredients, and for the sake of illustration they will be broken down into biologically inactive and biologically active components: The inactive ingredients of sports drinks are mostly for creating a pleasing taste or color. The ingredients are just natural or artificial flavors, and food dyes to make the drink look more appealing. Citric acid is used to give the drink a tart flavor and to preserve the product, thus giving it a longer shelf life.

Active ingredients are those that perform a function in the body itself. Water is perhaps the most important active ingredient in sports drinks. Though it is usually just a medium for chemical reactions, it is considered to be a biologically active ingredient. It replenishes the body of water lost through sweat and respiration, and helps all other physiological reactions to occur. Without water, no muscle contractions could take place, no nerve signals could be propagated, and no oxygen could reach any part of the body. Without water, the body cannot function.

Another active ingredient is sugar (carbohydrates). Simple sugars or starches (complex sugars) are all carbohydrates. Sugar is used in the form of many commercially available compounds: Sugary syrups like corn syrup, glucose, fructose, etc. These provide energy to the body. Most sports drinks contain simple sugars like glucose (C6H12O6) to be as quickly available to the body as possible.

Carbohydrates are the main source of energy for the body, and easily soluble in water, so their presence in sports drinks helps provide energy to the body. Though, ironically, sugar consumed immediately before or during exercise is not yet available to the body for fuel, so its presence in sports drinks is possibly unnecessary. But, sugars give the drink a sweet, pleasing taste, and when combined with the flavoring ingredients and citric acid it makes for a satisfying beverage.

Salts are added to the drink to help replenish the salts lost through perspiration. The high amount of salt in sports drinks often gives the drink a powerful, salty flavor. But, salty drinks are rarely thirst-quenching, so the added sugars in the drinks cover up the unpleasant flavor.

Electrolytes in the body

The major salts in the body make up about 2.3 kg in a 60 kg human body. These salts are: sodium, chloride, calcium, phosphorus, potassium, sulfur, and magnesium. Trace salts (iron, zinc, selenium, iodine, copper, manganese, fluoride, chromium, and others) may make up only about 2.5 g in that same 60 kg body, but still are very important in human physiology.

(Extrapolated from data - Whitney, p.177)

Sodium, Chloride and Potassium are the electrolytes of most concern in sports drinks are they are the most quickly lost through excretion:

Sodium – This ion is the most important in sports drinks. As the salt most concerned with the regulation of water in the body, its presence is invaluable. Sodium is involved with acid-base balance, and is essential to muscle contraction and nerve transmission.

Chlorine (Chloride) – This is the principal negative ion of the extracellular fluid and occurs primarily in association with sodium. Sodium Chloride (NaCl) is the common salt that contains these two ions, and is of the most concern in sports drinks.

Potassium – Potassium is the main positively charged ion inside the body. In addition to assisting with protein and carbohydrate metabolism, potassium is critical in heartbeat regulation. For example, most heart failure due to malnutrition is actually due to the loss of potassium.

Calcium, Phosphorus, Sulfur, and Magnesium are all extremely important in exercise physiology, but relatively stable in the body and not as necessary to replenish in sports drinks:

Calcium – 99% of the calcium in the body is contained in the bones, but the 1% contained in the blood is vital to human life. It helps regulate muscle contraction, transmit nerve impulses, and clot blood. It is also necessary for the secretion of hormones, digestive enzymes and neurotransmitters. When the body loses serum calcium (calcium in the blood), it draws on the supply of calcium in the bones to replenish those supplies, weakening the bone structure.

Phosphorus – Most (85%) of phosphorus in the body is combined with calcium crystals in the bones and teeth. Phosphorus is one of the body’s major buffers (as phosphoric acid) and is found in all body cells. It is also a major building block of DNA and RNA, and thus is necessary for all cell growth.

Sulfur – Sulfur is not used by the body in its elemental form, but is present in many amino acids and proteins.

Magnesium – Magnesium is rare in the body, and over half of it is stored in the bones, but its presence is necessary for the functioning of many enzymes. It is also necessary for correct muscle regulation, as its deficiency causes tetany (prolonged contraction). It is necessary for the relaxation of muscles after exertion and thus is important to athletes.

Electrolytes and Water in Exercise

Beginning athletes lose electrolytes much faster than seasoned athletes, but still the evidence doesn’t really support the necessity of sports drinks. Some sources claim that electrolyte replacement isn’t really necessary unless the person loses more than 5 to 10 pounds of sweat each day for several consecutive days. So, the common consumption of sports drinks isn\’t harmful, but may be superfluous. However, the water in those drinks is invaluable to performance, and is highly recommended for all athletes.

If a person does feel that their exercise regiment requires electrolyte replacement, they can make their own. A 1/3 teaspoon of table salt and 1 cup of fruit juice added to a quart of water closely mimics the isotonic fluid in the body that commercial sports drinks emulate. But, regular tap water (combined with a healthy diet) is usually enough to provide all the bodily needs for a person engaged in moderate exercise.

Works Consulted -Marieb, Elaine N., Human Anatomy & Physiology. Benjamin Cummings, 2001.

-Wikipedia, Sports Drinks. http://en.wikipedia.org/wiki/Sports_drink (accessed Sept. 2005)

- Wikipedia, Gatorade. http://en.wikipedia.org/wiki/Gatorade (accessed Sept. 2005)

-Whitney, Elanor N., Cataldo, Corrine B., DeBruyne, Linda K., Rolfes, Sharon R., Nutrition for Health and Health Care. West Publishing Company, 1996.