Exertional hyponatremia among U.S. active component service members, 2021-2025
MSMR
|June 17, 2026
Summary
Exertional hyponatremia, a dangerous fluid electrolyte disorder, saw decreased incidence in U.S. service members from 2024 to 2025. Continued monitoring is vital due to varying risk factors across demographics.
Area of Science:
- Sports Medicine
- Endocrinology
- Public Health
Background:
- Exertional hyponatremia (EH) is a serious condition caused by excessive fluid intake diluting serum sodium.
- It can impair neurological and organ functions and be fatal if not managed promptly.
- U.S. active component service members (ACSMs) are monitored for EH incidence.
Purpose of the Study:
- To analyze trends in exertional hyponatremia diagnoses among ACSMs from 2021 to 2025.
- To identify demographic and occupational groups with the highest EH incidence rates.
- To assess changes in EH rates within specific populations like the Marine Corps.
Main Methods:
- Retrospective analysis of diagnosed exertional hyponatremia cases among ACSMs.
- Calculation of incidence rates per 100,000 person-years (p-yrs).
- Stratification of data by demographics (age, sex, race) and occupation.
Main Results:
- Overall EH incidence decreased from 10.6/100,000 p-yrs in 2024 to 8.1/100,000 p-yrs in 2025.
- Highest 2025 rates were in males, 35-39 year olds, non-Hispanic Whites, healthcare occupations, and western U.S. stations.
- Significant declines in EH cases were noted in the Marine Corps and recruit populations between 2024-2025.
Conclusions:
- While overall EH incidence is declining, specific age groups (e.g., 35-39 years) show increasing rates.
- Targeted prevention strategies are necessary due to differential risk factor impacts.
- Continued surveillance of EH in military populations remains crucial.
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