Research
Mixed
Hyponatremia is a risk in ultra-endurance events, particularly when excessive water consumption occurs without adequate sodium replenishment, though it is uncommon in standard marathons.
During long events, monitor sodium intake alongside water. Drinking excessive plain water can lead to hyponatremia, especially in events lasting many hours. Follow event-specific hydration guidelines that account for sodium loss.
GoodQualifiesHIGH confidence
This is uncommon in events such as marathons... However, hyponatremia does appear to be more prevalent in longer events such as triple iron-man triathlons... with one such study reporting that 26% of the competitors had exercise-associated hyponatremia.
Why this rating
Based on specific studies cited regarding electrolyte concentrations in various endurance events.
Source
Acute changes to biomarkers as a consequence of prolonged strenuous running
Stephen R. Bird et al. · Annals of Clinical Biochemistry International Journal of Laboratory Medicine · 2013
DOI 10.1177/0004563213492147
narrative_reviewCited 58×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Prolonged strenuous running (e.g., marathons, ultra-marathons) causes acute, transient elevations in biomarkers typically associated with pathology (such as creatine kinase, cardiac troponins, and liver enzymes), but these changes represent physiological stress and tissue microtrauma rather than chronic disease or injury.Good
- Familiarity with the exercise modality significantly reduces the magnitude of biomarker elevation and the severity of Delayed Onset Muscle Soreness (DOMS) due to physiological adaptations.Good
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