The Ironman Triathlon is characterized for being an endurance activity consisting of 3.8 km of swimming, 180 km of cycling and 42.2 km of running, in which the athlete exercises an average of about 13 hours. In this context, the athlete exposed to such load of effort and environmental adversities, experiences acute organic alterations in his biological systems, including hydroelectrolytic disturbs. The objective of this study is to describe the hydric and electrolytic alterations found in Ironman triathlon athletes. From years 2002 to 2005, 109 volunteer athletes have been evaluated before and immediately after the events which took place in Florianópolis-SC Brazil, with blood analysis of sodium and potassium electrolytes, and body mass measurement. Sodium serum data from 89 athletes have been correlated with the degree of dehydration and percentage alterations of body weight. Data of 77 athletes concerning the serum potassium were separately evaluated in a descriptive way. Six athletes (6.7%) were euhydrated or superhydrated at the end of the test; 50 athletes were dehydrated from 0 to 3% (56.2%); 29 from 3 to 6 % (32.6%) and 4 athletes (4.5%) were dehydrated more than 6%. There was a tendency to hyponatremia among those who had dehydrated less or gained weight. Potassium behaved within the limits of normality in the entire sample. It was concluded that hydroelectrolytic disturbs (hyponatremia and dehydration) are recurrent in this sportive modality, being superhydration the probable etiology of hyponatremia denoted from profit or small weight loss.
Hyponatremia; Dehydration; Superhydration; Potassium
