Water Intoxication — Considerations for Patients , Athletes and Physicians

46 INTRODUCTION P rior to 1969 athletes were encouraged to avoid drinking any fluids during exercise since it was believed that fluid ingestion would impair exercise performance, in particular by causing gastrointestinal distress, the so-called “stitch.” Athletes in those years actively followed that advice, priding themselves on their ability to run even 26 mile (42 km) marathon races without drinking (1). Furthermore, the rules then governing competitive distance running restricted the amount of fluid to which athletes had access. In 1981 the first case of exercise-associated hyponatremic encephalopathy (EAHE) occurred in a 46-year-old female marathon runner in a 90 km Comrades ultramarathon in South Africa. She presented with the symptoms and signs typical of EAHE as listed in Table 1 (2). In 1991 we provided definitive evidence that exercise-associated hyponatremic encephalopathy (EAHE) is due to abnormal fluid retention in those who overdrink during prolonged exercise and to which a sodium deficit plays little or no part (3). Shortly after the publication of this compelling evidence, influential sporting organizations began to promote the value of drinking “as much as tolerable” but failed to warn of the proven dangers of overdrinking during exercise. As a result, more than 10 documented deaths from EAHE, an entirely preventable condition, have been reported in the scientific literature since 1991 (4). Water Intoxication—Considerations for Patients, Athletes and Physicians NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #66