Fluid and electrolyte replacement in soccer

To read the exercise physiology literature, you would assume that the initial research into the use of fluids for physical work began in the early to middle 1960s. The first work on humans performing physical work in the heat, however, was during the construction of the Hoover Dam in Nevada. The construction team worked in temperatures that typically ranged from 90° to 120°F, and the findings were published in the mid 1930s. Following this, the military conducted studies on work in the heat in preparation for desert warfare. In 1947, Adolph 1 summarized the work in Physiology of Man in the Desert . Although the exercise physiology textbooks did not pick up on the consequences of exercise in the heat until the 1960s, the basics had been under study for nearly half a century. In the sporting community, drinking fluids was considered a weakness and coaches and athletes alike withheld water during training and competition. It was not uncommon for marathoners to consume only 1 to 2 drinks during a race, and ultramarathoners might not take their first drink until the 75th mile of a 100-mile run. Unfortunately, the practice of withholding or refusing fluids during training for weight-limited sports is still practiced. There is probably more participation in team sports than any other type of athletic competition with soccer leading the way in total participation and basketball being the world's fastest growing sport. 5 Despite the immense popularity of team sports, little work has been completed on such a simple concept as fluid replenishment. Most of the guidelines are based on work directed at distance running, which does not take into account the unique features of team sports. The opposition is grim competition. Adding heat and fluid restriction places the athlete in an climate of severe competitive stress. Major competitions are routinely held in conditions that can compromise the performance and health of the athlete. Many of the games during the World Cup in 1994 and the Olympics in 1996 in the United States were contested in conditions many would choose not to play. Unfortunately, scheduling of such mass events as the Olympics, World Cup, or even a sponsored, single-event like a 10K cannot be postponed until the weather conditions are perfect. When an athlete has been living and training in a more temperate environment and must compete during high ambient heat, the potential for heat illness exists. History shows us heat illnesses during running events dating from Doranado Pietri in the 1908 Olympic Marathon to Gabrielle Andersen-Scheiss in the 1984 Olympic Marathon to the recent deaths of three wrestlers in the United States while attempting to “make weight.” This article discusses the factors associated with exercise in the heat and how heat affects sports performance. In addition, the role of fluids during exercise and soccer play in the heat are summarized. Hopefully, some respect for heat will be gained as well as confidence in the methods to minimize heat's role as an additional opponent for the soccer player.