Heat Cramps

Heat cramps-painful spasms in the legs and abdomen-are typically the result of a fluid and electrolyte imbalance caused by severe dehydration. They are most likely to occur in people who sweat heavily and who lose a higher than normal amount of sodium and other electrolytes (including potassium, calcium, and magnesium) in the sweat. For these individuals, drinking adequate amounts of sodium-containing beverages during exercise is particularly useful. Heat cramps appear to occur late in the day after consumption of large volumes of plain water.³⁷ At the first sign of involuntary muscle twitching or mild muscle cramping, athletes should consume 16 ounces (480 milliliters) of a sports drink that has been supplemented with a teaspoon of table salt.³⁸ This should then be followed by a steady intake of sodium-supplemented sports drinks for the remainder of the exercise session. To help meet the needs of athletes who experience frequent cramping, companies have developed products that provide a measured amount of sodium, potassium, calcium, and magnesium for adding to a given volume of sports beverage.

Table 3.6 Indications of Cramp-Prone Athletes

• History of heat cramps
• Consume inadequate sodium (eat a salt-restricted diet)
• Sweat profusely early in activity
• Have poor hydration habits during exercise
• Sweat is heavy in salt; stings eyes; tastes salty
• Visible (chalky) salt on body and clothing
• Not adapted to a hot and humid environment
• Family history of cystic fibrosis