Skip to main content
OpenTrials
Completed

NCT Number: NCT04767347

Renal Considerations in the Heat Stress Recommendations

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.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Hot Weather; Adverse Effect Body Temperature Changes Dehydration Heat Stress Disorders Hyperthermia Kidney Dysfunction Kidney Injury Metabolic Diseases Nutritional and Metabolic Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Signs and Symptoms Water-Electrolyte Imbalance Wounds and Injuries

Age range

18 year–44 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Public Health

Bloomington, Indiana, 47405-7109, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

23.0°C WBGT - Fixed Work Rate

Other

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

Other

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

Other

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

Other

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

Other

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

Other

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

Other

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)

Other

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

Primary outcomes

  1. Peak urinary [IGFBP7•TIMP-2]

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

Secondary outcomes

  1. Urinary NGAL

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

  2. Urinary IGFBP7

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

  3. Urinary TIMP-2

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

  4. Urinary IL-18

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

  5. Urinary L-FABP

    Time frame: through study completion, up to 20 weeks

    Kidney injury marker

  6. Renal artery blood velocity

    Time frame: through study completion, up to 20 weeks

    Index of kidney blood flow

  7. Segmental artery blood velocity

    Time frame: through study completion, up to 20 weeks

    Index of kidney blood flow

Other outcomes

  1. Core body temperature

    Time frame: through study completion, up to 20 weeks

    Heat strain variable

  2. Mean skin temperature

    Time frame: through study completion, up to 20 weeks

    Heat strain variable

  3. Oxygen uptake

    Time frame: through study completion, up to 20 weeks

    Heat strain variable

  4. Heart rate

    Time frame: through study completion, up to 20 weeks

    Heat strain variable

  5. Blood pressure

    Time frame: through study completion, up to 20 weeks

    Heat strain variable

  6. Whole-body sweat rate

    Time frame: through study completion, up to 20 weeks

    Hydration and heat strain variable

  7. Percentage change in body weight

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  8. Plasma osmolality

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  9. Urine osmolality

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  10. Blood and plasma volume

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  11. Urine specific gravity

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  12. Plasma copeptin

    Time frame: through study completion, up to 20 weeks

    Hydration status variable

  13. Creatinine clearance

    Time frame: through study completion, up to 20 weeks

    Kidney function variable

  14. Fractional excretion of electrolytes

    Time frame: through study completion, up to 20 weeks

    Kidney function variable

  15. Free water clearance

    Time frame: through study completion, up to 20 weeks

    Kidney function variable

  16. Serum uric acid

    Time frame: through study completion, up to 20 weeks

    Kidney function variable

  17. Urinary uric acid

    Time frame: through study completion, up to 20 weeks

    Kidney function variable

Sponsors and collaborators

Lead sponsor

Indiana University

Other

Collaborators

  • State University of New York at Buffalo

Registry information

Acronym: Aim1

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Feb 23, 2021
Registry last updated
Nov 8, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.