Renal Considerations in the Heat Stress Recommendations (Aim2)

Study Overview
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Brief Summary
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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.

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

Conditions
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Hot Weather; Adverse Effect, Kidney Dysfunction, Kidney Injury, Hyperthermia, Dehydration

Intervention / Treatment
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* Procedure: Fluid replacement
* Procedure: No fluid replacement


Participation Criteria
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Eligibility Criteria
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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+.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 44 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

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

What is the study measuring?
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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 |