| The purpose of this study was to quantify the fluid intake of athletes competing in the 2000 IRONMAN Triathlon® World Championship and to determine if fluid consumption was related to a physiological condition, hyponatremia, that is prevalent in ultraendurance events. Twenty-five triathletes who received medical attention after completing the race were surveyed during their stay in the medical tent to quantify and describe fluid and sodium intake before and during the race. The survey recorded the athlete's physical characteristics, race finish information, and plasma sodium concentration, if available. The survey also recorded fluid and food consumption before and during the race and was sectioned into race segments to aid the athletes' recall. Information obtained about fluid and food consumption reflected the type, brand, and quantity consumed. Sodium intake was calculated from various sources including fluid, food, energy bars, carbohydrate gels, and sodium tables.; The sample was divided into two groups (hyponatremic and non-hyponatremic) based on plasma sodium concentration or, absent of electrolyte data, physician's diagnosis. Hyponatremia was defined as a plasma sodium concentration of less than 135 mEq/L. Athletes categorized as hyponatremic consumed 47.8% more total fluid (23.48 ± 8.58 vs. 15.89 ± 6.96 L) than the non-hyponatremic athletes (P = 0.024). Consumption of carbohydrate-electrolyte beverage was not significantly different (12.55 ± 5.14 vs. 11.95 ± 6.56 L), but the hyponatremic athletes consumed 177.7% more water (10.94 ± 5.61 vs. 3.94 ± 3.63 L) during the race than the non-hyponatremic athletes (P = 0.001). The results of this study suggest that hyponatremia during ultraendurance events is related to an excess consumption of water, a hypotonic fluid. |
