Cooling Solutions for Outdoor Workers

Not Applicable

• Conditions: Hyperthermia; Heat Acclimation and Thermotolerance

• Registration Number: NCT06998667
• Lead Sponsor: Stanford University

Brief Summary

The investigators aim to test the effectiveness of two cooling interventions in reducing the core temperature of outdoor workers.

Detailed Description

Workers in a variety of US industries-construction workers, welders, farmers, firefighters, and warehouse workers among them-are at risk for hyperthermia during work, yet very few interventions are being developed to mitigate heat related organ injury, particularly when workers do not have obvious symptoms of heat related illness. The investigators plan to test whether two active cooling technologies can help mitigate hyperthermia and risk for kidney injury. This work will enhance worker safety using evidence-based technology.

To accomplish the aims of testing two active cooling interventions, the investigators plan to implement a case-cross over randomized control trial design at the work site conducted in partnership with an employer and with 30 workers at risk for hyperthermia. Over three sequential weeks, the investigators will measure rate of core temperature change (primary outcome). Secondary outcomes will include changes in kidney injury markers; changes in worker productivity; and worker acceptability of interventions.

Study Timeline

• Study First Submitted: 2025-05-20
• Study First Submitted QC: 2025-05-29
• Study First Posted: 2025-05-31
• Status Verified: 2025-06
• Study Start: 2025-06-24
• Last Update Submitted: 2025-06-30
• Last Update Posted: 2025-07-03
• Primary Completion: 2025-10-15
• Study Completion: 2026-01-15

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

1. Age ≥ 18
2. Anticipated to be working in the same job category for the duration of the study
3. Able to communicate in English or Spanish

Exclusion Criteria

1. Cannot provide informed consent
2. Weight less than 40 kg
3. Inability to swallow pills
4. Known history of having a pacemaker or ICD
5. Pregnancy as determined by self report and confirmed on Day 1
6. Gastrointestinal disorders (e.g., gastroparesis, prior surgery on GI tract with the exception of appendectomy or cholecystectomy, diverticulosis or inflammatory bowel disease)
7. Plan for an elective MRI in the 7 days post last planned pill ingestion

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Core Temperature	up to 10 hours	Rate of core temperature change as measured by core temperature pill

Trial Locations

Locations (1)

Stanford University; 🇺🇸 Palo Alto, California, United States