Fatal hyponatremia is becoming a serious problem especially for serious athletes who are involved in intensive training. It has common in marathon runners and military recruits, as well as, anyone else in intensive training.
Fatal hyponatremia in athletes is rare, but it has claimed the lives of marathon runners and military recruits, and should therefore be brought to the attention of sports/health professionals. However, it is clear from epidemiological (population) data that hyponatremia associated with prolonged exercise is quite rare. It is very important to keep the risk of 'overhydration' in perspective. For example, one study of 'higher risk' athletes who developed symptomatic hyponatremia were participating in distance running events of 42 km and triathlons lasting 9–12 h.