Hydration Strategies, Weight Change and Performance in a 161 km Ultramarathon
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ABSTRACT: This work examines whether sodium supplementation is important in prevention of hyponatremia during continuous exercise up to 30 hours, and if any distinguishing characteristics of those developing hyponatremia could be identified. Participants of the 161-km Western States Endurance Run underwent body weight measurements before, during and after the race, completed a post-race questionnaire about drinking strategies and use of sodium supplementation during four race segments, and underwent analysis of post-race serum sodium concentration. The post-race questionnaire was completed by 74.5% of the 376 starters, a post-race blood sample was provided by 61.1% of the 296 finishers, and 53.0% of finishers completed the post-race survey and also provided a post-race blood sample. Among this population, the incidence of hyponatremia among finishers was 6.6%, and sodium supplements were used by 93.9% of the runners. Post-race serum sodium concentration was found to be directly related to the rate of sodium intake in supplements (r=0.24, p=0.0027) and indirectly related to the percentage change in body weight from immediately before the race start (r=-0.19, p=0.10). There was no difference in rate of sodium intake in supplements between the hyponatremic and normonatremic finishers, and none of the hyponatremic finishers lost >4.3% body weight. Hyponatremic finishers were not distinguished from normonatremic or hypernatremic finishers by other runner characteristics considered, drinking strategies or gastrointestinal symptoms of nausea and vomiting. We conclude that a low sodium intake in supplements has minimal responsibility for development of hyponatremia during continuous exercise up to 30 hours, whereas overhydration is the primary characteristic of those developing hyponatremia. Therefore, avoiding overhydration appears to be the most important means for preventing hyponatremia under these conditions.
Questions & Answers about this publication
- What are the effects of dehydration in ultra-endurance runners?
If anyone knows the answer or know of any related article please answer me
maybe you can use the following studies:
Knechtle B, Duff B, Schulze I, Kohler G. A multi-stage ultra-endurance run over 1,200 KM leads to a continuous accumulation of total body water. J Sports Sci Med. 2008;7(3):357-64. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761892/pdf/jssm-07-357.pdf
Winger JM, Hoffman MD, Hew-Butler TD, Stuempfle KJ, Dugas JP, Fogard K, Dugas LR. The effect of physiology and hydration beliefs on race behavior and postrace sodium in 161-km ultramarathon finishers. Int J Sports Physiol Perform. 2013;8(5):536-41. https://www.researchgate.net/publication/235630016_Physiology_and_Hydration_Beliefs_Affect_Race_Behavior_but_not_Post-Race_Sodium_in_161-km_Ultramarathon_Finishers
Hoffman MD, Hew-Butler T, Stuempfle KJ. Exercise-associated hyponatremia and hydration status in 161-km ultramarathoners. Med Sci Sports Exerc. 2013 Apr;45(4):784-91. doi: 10.1249/MSS.0b013e31827985a8. https://www.researchgate.net/publication/233331364_Exercise-Associated_Hyponatremia_and_Hydration_Status_in_161-km_Ultramarathoners
Hoffman MD, Stuempfle KJ. Hydration strategies, weight change and performance in a 161 km ultramarathon. Res Sports Med. 2014;22(3):213-25. doi: 10.1080/15438627.2014.915838. https://www.researchgate.net/publication/263288907_Hydration_Strategies_Weight_Change_and_Performance_in_a_161_km_Ultramarathon
Kao WF, Hou SK, Chiu YH, Chou SL, Kuo FC, Wang SH, Chen JJ. Effects of 100-km ultramarathon on acute kidney injury. Clin J Sport Med. 2015;25(1):49-54. doi: 10.1097/JSM.0000000000000116. https://www.researchgate.net/publication/263290263_Effects_of_100-km_Ultramarathon_on_Acute_Kidney_Injury
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