Renal Considerations in the Heat Stress Recommendations
Condition: Hot Weather; Adverse Effect; Kidney Dysfunction; Kidney Injury; Hyperthermia; Dehydration
MeSH terms: Dehydration; Hyperthermia
Study type: Interventional

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.
    


Intervention name(s): 23.0°C WBGT - Fixed Work Rate; 25.5°C WBGT - Fixed Work Rate; 27.5°C WBGT - Fixed Work Rate; 28.5°C WBGT - Fixed Work Rate; 35.5°C WBGT - Fixed Work Rate; 26.0°C WBGT - Fixed work-to-rest ratio; 30.5°C WBGT - Fixed work-to-rest ratio; 30.5°C WBGT - Fixed work-to-rest ratio (high intensity)
Intervention type(s): Other; Other; Other; Other; Other; Other; Other; Other
Intervention description(s): 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; 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; 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; 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; 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; 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; 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; 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
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This study will systematically examine the NIOSH recommendations for prescribing work-to-rest ratios during occupational heat stress on kidney function.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Basic Science