Renal Considerations in the Heat Stress Recommendations

Dehydration Clinical Trial

— Aim1  

Official title:

Renal Considerations in the Heat Stress Recommendations

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04767347
• Other study ID #: 1902420140
• Status: Completed
• Phase: N/A
• Start date: March 1, 2021
• Est. completion date: May 4, 2023

Study information

• Verified date: November 2023
• Source: Indiana University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

An epidemic of chronic kidney disease is occurring in laborers who undertake physical work outdoors in hot conditions. The reason for this is unknown, but may be related to kidney dysfunction caused by increases in body temperature and dehydration. The current heat stress recommendations for workers were not developed with regards for kidney health. The purpose of this study is to determine if the current recommendations protect against kidney dysfunction.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 38
• Est. completion date: May 4, 2023
• Est. primary completion date: May 4, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 44 Years

Eligibility

Inclusion Criteria:

• Men and women
• 18-44 y old
• Body mass index =35.0 kg/m2
• Self-reported to be healthy.

Exclusion Criteria:

• Not within defined age range
• Estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m2
• Deemed highly active according to the physical activity questionnaire (i.e., >3500 MET*min/wk)
• Body mass index >35.0 kg/m2
• Current or history of any renal disease, heart disease, stroke, immune or autoimmune disease, and/or gastrointestinal disease/surgery
• Hypertension during screening (systolic blood pressure >139 or diastolic blood pressure >89)
• Using medications that blunt the physiological response to exercise (e.g., beta blockers)
• Prescription medication with a known side effect of impaired temperature regulation or fluid balance (e.g., diuretics)
• Positive pregnancy test at any time during the study or breast feeding
• Current tobacco or electronic cigarette use or consistent use within the last 2 years
• Inability to safely complete the peak oxygen uptake test

Related Conditions & MeSH terms

• Dehydration
• Hot Weather; Adverse Effect
• Hyperthermia
• Kidney Dysfunction
• Kidney Injury

Intervention

Other:
• 23.0°C WBGT - Fixed Work Rate
For four hours, participants will walk on a treadmill to elicit 430 W of metabolic heat production in the following conditions: 23.0°C WBGT (29°C, 46% relative humidity) @ 60 min exercise per hour
• 25.5°C WBGT - Fixed Work Rate
For four hours, participants will walk on a treadmill to elicit 430 W of metabolic heat production in the following conditions: 25.5°C WBGT (31°C, 52% relative humidity) @ 45 min exercise per hour
• 27.5°C WBGT - Fixed Work Rate
For four hours, participants will walk on a treadmill to elicit 430 W of metabolic heat production in the following conditions: 27.5°C WBGT (33°C, 53% relative humidity) @ 30 min exercise per hour
• 28.5°C WBGT - Fixed Work Rate
For four hours, participants will walk on a treadmill to elicit 430 W of metabolic heat production in the following conditions: 28.5°C WBGT (34°C, 54% relative humidity) @ 15 min exercise per hour
• 35.5°C WBGT - Fixed Work Rate
For four hours, participants will walk on a treadmill to elicit 430 W of metabolic heat production in the following conditions: 35.5°C WBGT (40°C, 65% relative humidity) @ 15 min exercise per hour
• 26.0°C WBGT - Fixed work-to-rest ratio
For four hours, participants will walk on a treadmill at differing levels of metabolic heat production and environmental conditions (noted below), but at a fixed work-rest ratio of 30 minutes per hour. 26.0°C WBGT (31°C, 55% relative humidity) @ 530 W metabolic heat production
• 30.5°C WBGT - Fixed work-to-rest ratio
For four hours, participants will walk on a treadmill at differing levels of metabolic heat production and environmental conditions (noted below), but at a fixed work-rest ratio of 30 minutes per hour. 30.5°C WBGT (36°C, 55% relative humidity) @ 230 W metabolic heat production
• 30.5°C WBGT - Fixed work-to-rest ratio (high intensity)
For four hours, participants will walk on a treadmill at differing levels of metabolic heat production and environmental conditions (noted below), but at a fixed work-rest ratio of 30 minutes per hour. 30.5°C WBGT (36°C, 55% relative humidity) @ 530 W metabolic heat production

Locations

Country	Name	City	State
United States	School of Public Health	Bloomington	Indiana

Sponsors (2)

Lead Sponsor	Collaborator
Indiana University	State University of New York at Buffalo

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Core body temperature	Heat strain variable	through study completion, up to 20 weeks
Other	Mean skin temperature	Heat strain variable	through study completion, up to 20 weeks
Other	Oxygen uptake	Heat strain variable	through study completion, up to 20 weeks
Other	Heart rate	Heat strain variable	through study completion, up to 20 weeks
Other	Blood pressure	Heat strain variable	through study completion, up to 20 weeks
Other	Whole-body sweat rate	Hydration and heat strain variable	through study completion, up to 20 weeks
Other	Percentage change in body weight	Hydration status variable	through study completion, up to 20 weeks
Other	Plasma osmolality	Hydration status variable	through study completion, up to 20 weeks
Other	Urine osmolality	Hydration status variable	through study completion, up to 20 weeks
Other	Blood and plasma volume	Hydration status variable	through study completion, up to 20 weeks
Other	Urine specific gravity	Hydration status variable	through study completion, up to 20 weeks
Other	Plasma copeptin	Hydration status variable	through study completion, up to 20 weeks
Other	Creatinine clearance	Kidney function variable	through study completion, up to 20 weeks
Other	Fractional excretion of electrolytes	Kidney function variable	through study completion, up to 20 weeks
Other	Free water clearance	Kidney function variable	through study completion, up to 20 weeks
Other	Serum uric acid	Kidney function variable	through study completion, up to 20 weeks
Other	Urinary uric acid	Kidney function variable	through study completion, up to 20 weeks
Primary	Peak urinary [IGFBP7•TIMP-2]	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Urinary NGAL	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Urinary IGFBP7	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Urinary TIMP-2	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Urinary IL-18	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Urinary L-FABP	Kidney injury marker	through study completion, up to 20 weeks
Secondary	Renal artery blood velocity	Index of kidney blood flow	through study completion, up to 20 weeks
Secondary	Segmental artery blood velocity	Index of kidney blood flow	through study completion, up to 20 weeks