In the modern era where sport technology has played such an important role in the training programs formulated for both elite competitors and recreational athletes seeking a personal best, sophisticated sports drinks and gel products abound in the nutritional supplement market. The simple salt tablet is a decidedly "old school" athletic supplement.
Salt in its natural mineral form is one of the oldest known diet supplements. The effect on the function of the body of one of salt's constituent elements, sodium, has been well understood for at least two centuries. Formed into salt tablets, salt was used by laborers in warm, heavy industrial environments of North America in the late 1800s; it was also provided to soldiers by a number of national armies during World War II to assist combatants in dealing with dehydration in hot jungle and desert environments. For more than 50 years, salt tablets have been a staple in North American preseason football training camps, which are often held in the heat of July and August.
Unlike some of the modern-age training supplements that are marketed with little scientific backing for the claims advanced as to effectiveness, there is no scientific question concerning the benefits of salt, and particularly sodium, for athletes involved in warm weather sports.
Sodium is directly related to the body's ability to perform. Sodium is of primary importance in its role as a regulator of how much fluid is present in the body at any time, both in terms of volume, which ultimately will impact on the blood volume available to the cardiovascular system for all of its processes associated with human performance, as well as sodium's role in relation to the maintenance of the acid/base (pH) balance throughout the body. Muscle energy is developed through a complex series of processes in the individual cells, a portion of which is tied to the "pump" mechanism established through the proper balance between potassium and sodium in the intracellular fluids that support each cell. A sodium deficit can have a catastrophic effect on one or all of these human systems. The condition known as hyponatremia is the ultimate result of a sodium deficit, in which the body's sodium imbalance is so severe that even when dehydrated, the body will not absorb available water from the stomach through the small intestine because the sodium level has triggered the body to take no more water without sodium being available.
Sodium is lost to the body during exercise through perspiration and urine excretion. Sodium can only be replaced through dietary sources or supplements; the body has no independent mechanism to warehouse sodium.
In warm weather exercise, the amount of sodium that an athlete may lose through perspiration is varied. Athletes who are acclimatized to warm environmental conditions of high temperatures and humidity will generally lose less sodium per volume of perspiration than those who are not so accustomed to the conditions. A typical adult will lose sodium at a rate ranging between 100 mg and 700 mg per liter, and the athlete will lose between 1.0 l to 2.5 l of fluid to perspiration per hour, subject to variables such as intensity and body type. Most commercial sport drink products contain sodium, but the typical quantity ranges between 50 mg and 170 mg of sodium per 8 oz (250 ml) bottle, meaning that the consumption of sport drinks, while a benefit, in terms of fluid replacement, is not necessarily a solution to sodium deficit. To achieve sodium replacement through the sports drink, the formulation might taste more like seawater than a sports drink. Five hundred milligram-sized salt tablets, which are chemically 40% sodium and thus provide approximately 200 mg of sodium to the athlete, might assist the athlete in counteracting a sodium deficit.
Salt tablets present problems for athletes if taken orally to correct sodium deficiencies. In their raw form, salt tablets are often difficult to digest, causing gastric irritation, with accompanying nausea and diarrhea a common side effect. The stomach has difficulty in the immediate digestion of salt tablets, meaning that the benefit of the sodium is delayed; sports drinks, and their nutrients, are far easier for the body to absorb. Swallowed alone, without significant fluid to accompany the salt tablet, the sodium will act to further accelerate the dehydration of the body.
In endurance races, such as triathlons, the Iron-man, marathon, and ultra-marathon running, and ultra cycling events, salt tablets have been successfully employed as a supplement to the sports drink supplements. Salt tablets, taken either with sports drinks (that have their own sodium component) or fruit drinks that naturally contain potassium, serve to increase the sodium levels in a form that is far easier to digest and therefore be of more immediate use to the fluid level and acid/base balance of the body.
Salt tablets, even when consumed with a volume of sports drink, should be tested; the athlete can ingest the tablets during training to determine how the athlete's body will react after they are consumed.