Renal Considerations in the Heat Stress Recommendations (Aim2)

Renal Considerations in the Heat Stress and Hydration Recommendations (Aim 2)

An epidemic of chronic kidney disease is occurring in laborers who undertake physical work outdoors in hot conditions. The reason for this is largely unknown, but may be related to kidney dysfunction caused by increases in body temperature and dehydration that elicit oxidative stress and inflammation in the renal tubules. The purpose of this study is to determine whether hydration status modifies the development of renal oxidative stress and inflammation.

Study Overview

• Status: Completed
• Conditions: Hyperthermia; Kidney Injury; Dehydration; Kidney Dysfunction; Hot Weather; Adverse Effect
• Intervention / Treatment: Procedure: Fluid replacement; Procedure: No fluid replacement

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Indiana
    • Bloomington, Indiana, United States, 47405-7109
      • School of Public Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 44 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

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
• 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
• Answered "Yes" to any question on Page 1 of the PAR-Q+.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fluid replacement	Procedure: Fluid replacement; Participants will drink Gatorade Zero ad libitum, up to 1 cup every 15 minutes.
Sham Comparator: No fluid replacement	Procedure: No fluid replacement; Participants will not be permitted to drink.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak urinary thioredoxin	Marker of renal oxidative stress	Through study completion, up to twelve weeks
Peak urinary MCP-1	Marker of renal inflammation	Through study completion, up to twelve weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak urinary [IGFBP7 x TIMP-2]	Kidney injury marker	Through study completion, up to twelve weeks
Renal artery blood velocity	Measure of kidney blood flow	Through study completion, up to twelve weeks
Segmental artery blood velocity	Measure of kidney blood flow	Through study completion, up to twelve weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Core body temperature	Heat strain variable	Through study completion, up to twelve weeks
Mean skin temperature	Heat strain variable	Through study completion, up to twelve weeks
Oxygen uptake	Heat strain variable	Through study completion, up to twelve weeks
Heart rate	Heat strain variable	Through study completion, up to twelve weeks
Blood pressure	Heat strain variable	Through study completion, up to twelve weeks
Percentage change in body weight	Hydration status variable	Through study completion, up to twelve weeks
Blood and plasma volume	Hydration status variable	Through study completion, up to twelve weeks
Plasma osmolality	Hydration status variable	Through study completion, up to twelve weeks
Urine osmolality	Hydration status variable	Through study completion, up to twelve weeks
Urine specific gravity	Hydration status variable	Through study completion, up to twelve weeks
Creatinine clearance	kidney function variable	Through study completion, up to twelve weeks

Collaborators and Investigators

• Sponsor: Indiana University
• Collaborators: State University of New York at Buffalo

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2022
• Primary Completion (Actual): May 22, 2023
• Study Completion (Actual): May 22, 2023

Study Registration Dates

• First Submitted: July 11, 2022
• First Submitted That Met QC Criteria: July 13, 2022
• First Posted (Actual): July 14, 2022

Study Record Updates

• Last Update Posted (Estimated): November 8, 2023
• Last Update Submitted That Met QC Criteria: November 6, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Metabolic Diseases; Wounds and Injuries; Body Temperature Changes; Heat Stress Disorders; Water-Electrolyte Imbalance; Hyperthermia; Dehydration
• Other Study ID Numbers: 15402 (Stanford University IRB)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No