Critical Assessment of the Recommended Alert Limit Curves for Occupational Heat Exposure.

Background: Occupational heat stress recommendations aim to achieve thermal equilibrium and keep core temperature (T) below 38.0°C. We assessed the recommended alert limit curves when: (1) work-rest ratios are adjusted based on wet-bulb globe temperature (WBGT) at a fixed rate of metabolic heat production (H) and (2) H is adjusted based on WBGT at a fixed work-rest ratio.

Creatinine clearance is maintained in a range of wet-bulb globe temperatures and work-rest ratios during simulated occupational heat stress.

We tested the hypothesis that compliance with the National Institute for Occupational Safety and Health (NIOSH) heat stress recommendations will prevent reductions in glomerular filtration rate (GFR) across a range of wet-bulb globe temperatures (WBGTs) and work-rest ratios at a fixed work intensity. We also tested the hypothesis that noncompliance would result in a reduction in GFR compared with a work-rest matched compliant trial. Twelve healthy adults completed five trials (four NIOSH compliant and one noncompliant) that consisted of 4 h of exposure to a range of WBGTs.

Occupational Heat Stress Recommendation Compliance Attenuates AKI Risk Compared with a Work-Rest Ratio-Matched, Positive Control Scenario.

Occupational heat stress recommendations attenuate AKI risk compared with a work–rest ratio–matched positive control scenario. Heat-induced AKI risk is strongly related to peak core temperature. The peak change in serum creatinine largely paralleled peak changes in urinary [insulin-like growth factor-binding protein 7·tissue inhibitor metalloproteinase 2].

Ad libitum drinking prevents dehydration during physical work in the heat when adhering to occupational heat stress recommendations.

Government entities issue recommendations that aim to maintain core temperature below 38.0°C and prevent dehydration [>2% body mass loss] in unacclimated workers exposed to heat. Hydration recommendations suggest drinking 237 mL of a cool sport drink every 15-20 min.