Sodium and fluid balance among military participants of the 4-Day Marches

Sodium and fluid balance among military participants of the 4Day Marches: An explorative 'n-of-1' study on continuous monitoring of physiological signals (the SAFETY study) - Sodium and fluid balance among military participants of the 4-Day Marches - SAFETY studie

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

NL-OMON

Registry ID

NL-OMON61316

Enrollment

Registered

2026-04-14

Start date

2026-07-20

Completion date

Unknown

Last updated

2026-07-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Sodium and fluid imbalance during physical activity Regulation of sodium and fluid imbalance

Interventions

Results of the military participants will be compared against a historical cohort of age- and sex-matched non-military controls who performed exercise under comparable ambient conditions. This allows

Eligibility

Age

18 Years to 64 Years

Inclusion criteria

Inclusion criteria: =18 years oldBe a Dutch military participant of the 4-Day MarchesAble to understand and perform the study procedures

Exclusion criteria

Exclusion criteria: Foreign military participant of the 4-Day MarchesExclusion criteria associated with the use of the temperature capsule e-Celcius: body weight <36.5 kg, an implanted electro-medical device, a history of obstructive/ inflammatory bowel disease or surgery, or a scheduled MRI scan within 5 days of the experiment.Exclusion criteria associated with the use of the physical activity monitor Garmin Tactix 7: Implanted medical devices e.g. pacemaker, individuals with severe skin sensitivity.

Design outcomes

Primary

Measure	Time frame
For our primary objective, the primary study parameter is sodium balance, as measured by post-exercise plasma sodium levels (following venous blood collection). As secondary outcomes we examine fluid balance by urinary specific gravity levels, but also changes in body weight. For our secondary objective, we perform continuous monitoring of heart rate, physical activity (both using the wearable Heart Guard-shirt) and core body temperature (using the ingestible E-Celsius capsule).	—

Measure

Time frame

For our primary objective, the primary study parameter is sodium balance, as measured by post-exercise plasma sodium levels (following venous blood collection). As secondary outcomes we examine fluid balance by urinary specific gravity levels, but also changes in body weight. For our secondary objective, we perform continuous monitoring of heart rate, physical activity (both using the wearable Heart Guard-shirt) and core body temperature (using the ingestible E-Celsius capsule).

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Secondary

Measure	Time frame
For our secondary objective, we perform continuous monitoring of heart rate, physical activity (both using the wearable Heart Guard-shirt) and core body temperature (using the ingestible E-Celsius capsule).	—

Countries

Netherlands

Contacts

Public ContactE van der Gaag

Radboud Universitair Medisch Centrum

emma.vandergaag@radboudumc.nl0630069453

Outcome results

None listed

Source: NL-OMON (via WHO ICTRP) · Data processed: Jul 23, 2026