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The Impact of Self-assessment on Hydration

The Impact of Self-assessment on Wildland Firefighter and Surrogate Population Hydration

Status
Enrolling by invitation
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06954909
Enrollment
38
Registered
2025-05-02
Start date
2025-04-22
Completion date
2026-12-30
Last updated
2026-05-08

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

Conditions

Hydration Status

Keywords

Urine osmolality, Urine specific gravity, Labelled water (D20), Deuterium, Education, Self-assessment, Tactical operators, Firefighters, Women, Men, Healthy subjects

Brief summary

The studies objective is to assess the efficacy of hydration education and the use of a self-assessment worksheet vs. a no-intervention control on improving fluid intake and hydration status in underhydrated wildland firefighters (WLFFs) and their surrogates. Part I allows to understand hydration status of the participants (screening phase), Part II confirms if participants indeed are deemed to be low fluid consumers, and Part III of this research is a clinical trial that will focus on the optimization of hydration by improving fluid intake (and as a result lowering urine concentration) allowing participants theoretically to improve exercise performance (acute) and optimize health on the long term.

Detailed description

Enrollment will take place until enough people have been screened and be eligible to be enrolled in PART III of the study. Aside from allowing the investigators to better understand the hydration status of participants in PART I, this part will help to determine potentially eligible participants that can be confirmed through PART II by collecting again a urine sample, and if again concentrated urine is confirmed the research team will take a 5 mL venous blood draw performed by a trained phlebotomist to confirm elevated a copeptin level. These confirmed participants can then be enrolled in PART III of the study when eligible. PART I includes all participants: Two urine samples and questionnaire at one day. Expected duration of 2-3 minutes per urine sample and 2-3 minutes for the participant demographics questionnaire which will also be used as a screener to identify eligibility for PART II and III. PART II includes a smaller sample: Collection of a urine sample and a blood sample at one follow up day for the duration of 10 minutes. PART III, the intervention study (being a clinical trial): Includes n=38 participants, that will invest a maximum of 2 hours and 15 minutes as part of the data collection over a period of 6 days, which includes: * Education session (pre: INT, or post: CON) of 25 minutes. * Consuming labelled water and providing a urine sample and bodyweight the day before the start of the study, 10-15 minutes. * Participate in the study for 6 days (during normal work days) and bodyweight will be measured at day 2, 4 and 6 of the study, during all study days both INT and CON will provide a morning urine sample (and if possible an afternoon/evening sample after work), and during each days sensors will be attached to participants upper arm and gear, 5 minutes per day, 25-30 minutes total. * The intervention group will track its use of the tools we have provided them with, while the other group will not perform any additional self-assessments during the study period, 10 minutes per day 25-50 minutes total. * Final hydration strategy questionnaire for INT and CON, 5-10 minutes. Allocation to INT or CON depends on the total number of participants at different locations that will be eligible. The investigators will try to match participants based on their sex, age and bodyweight, and then randomly assign these matched participants to the intervention or placebo.

Interventions

BEHAVIORALHydration education and self-assessment

Hydration education is a 25-minute session based on the theory of planned behavior, including the instructions how to use a worksheet for hydration self-assessment and materials.

Sponsors

Arizona State University
Lead SponsorOTHER
Federal Emergency Management Agency
CollaboratorFED

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE

Intervention model description

Allocation to intervention (INT) or control (CON) depends on the total number of participants at different locations that will be eligible. The investigators will try to match participants based on their sex, age and bodyweight, and then randomly assign these matched participants to the intervention or control group. The control group participants will be offered to follow the education session after data collection has been finished.

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes

Inclusion criteria

The study plans to include firefighters from the Tonto National Forest and the broader Phoenix Valley area, and if needed, other active populations that are similarly active to WLFFs. Participants with high urine concentration (≥1.020 USG) for both samples collected during Part I (screening phase), may be invited to provide an additional urine sample and a blood sample for copeptin analysis during a follow up day (Part II). Participants with elevated USG and copeptin are eligible to participate in the study. Inclusion for PART I is that participants are part of a by the research selected wildland firefighter population (or surrogate population), no further

Exclusion criteria

are followed for PART I. For Part II and Part III the following criteria apply: Inclusion Criteria: * Age 18-65 years * Identifying as male, female or other

Design outcomes

Primary

MeasureTime frameDescription
Fluid turnoverOver a period of 4 days, in two 48-hour segments.Fluid turnover based on D2O analysis
Urine concentrationAfternoon sample day 1, morning sample day 2/4/6Urine concentration (osmolality).

Secondary

MeasureTime frameDescription
Urine concentrationAfternoon sample day 1, morning (and potential afternoon) samples day 1/2/3/4/5/6.Urine concentration (USG ) for morning and when available afternoon/evening samples.
ActivityThroughout the study during working hours, which may vary between 8-16 hours per working day.Activity pattern using an activity tracker attached to the upper arm to allow comparing activity between INT and CON.
Hydration strategyDay 6 of the data collection, covering the hydration strategy during the study period.Retrospective hydration strategy (questionnaire) of INT and CON.
Heat stressThroughout the study during working hours, which may vary between 8-16 hours per working day.Direct experienced environmental heat, measured by a heat sensor mounted on helmet or gear.
INT: Self-reported hydration measuresStudy days 2/3/4/5/6.Self-reported hydration measures in INT only (daily fluid intake in mL).

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 9, 2026