Incidence of Hyponatremia During a Continuous 246-km Ultramarathon Running Race The purpose of this study was to examine the incidence of the stress-associated hyponatremia in a 246 km long ultra-marathon. Over a period of two years, 63 male participants in the annual savat sound of Athens to Sparta, Greece, in the data analysis were included. A blood sample was taken from the day before the race as well as within 15 minutes of the race and analyzed on the sodium concentration. During the second year of data collection, blood was also removed on 93 km long checkpoint (n = 29).Size and weight were measured before and after the race. The average competition time of all subjects was 33 ± 3 hours with a range of 23.5 and 36.0 hours. Of the 63-recruited finishers, nine the race began with values that indicate a slight hyponatemia.Seven runners were classified at 93 km long checkpoint with a hyponatremia, three of which had a sodium level with severe hyponatemia. After the race, a total of 41 finishers (65%) developed either a slight (n = 27, 43%) or a heavy hyponatremia (n = 14, 22%). The average change in body weight percentage and serum sodium from the race to after the race was -3.6 ± 2.7% (-2.5 ± 1.9 kg) or -6.6 ± 5.6 mmol × L-1. The serum sodium mirror before the race was not a significant predictor of serum sodium levels after the race, but there was a significant and negative relationship between the change in body weight percentage and the serum sodium concentration after the race.
The incidence of eah of 52 and 65%, when these persons were excluded or included with hyponatremia before the race, was the highest in the current literature. The whole work can be found under https://pubmed.ncbi.nlm.nih.gov/31681787/