Hot-Weather Exercisers Need Salt to Avoid Fatigue

Fatigue during hot-weather exercise is caused by lack of water, salt, sugar or calories. Of the four, exercisers are most ignorant of their sodium needs. A study from The University of Otago in New Zealand shows that taking a salty drink prior to competition can help an athlete to exercise longer and harder (Medicine and Science in Sports and Exercise, January, 2007; and Clinical Journal of Sport Medicine, January 2007). Athletes who took the salty drink had larger blood volumes and greater endurance. Salt makes you thirsty earlier so you drink more, and salt in your body holds water so you have more water available to meet your needs.

In 1942, James Gamble of Harvard Medical School was hired to establish guidelines for soldiers fighting in the very hot climate of the South Pacific. He found that the only mineral needed for exercise in hot weather is sodium, found in common table salt. As a result of his studies, salt tablets were recommended for people who worked or exercised in hot weather, but since they caused stomach problems and because of concerns about high blood pressure, salt tablets were abandoned in the 1970s.

Salty drinks taste bad, so it is easier to meet your needs with salted foods. If you plan to exercise for more than a couple hours in hot weather, drink one or two cups of the liquid of your choice each hour and eat a salty food such as salted peanuts.
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