Introduction High-heat exposures at workplaces have particularly increasing adverse occupational health consequences across the globe, which will be an increasing problem as climate change progresses. Working people with moderate or heavy work intensity in hot environments are at particular risk especially in middle- and low-income tropical and subtropical regions, where protective workplace policies/optimal controls are not in place. This lecture presents evidence on occupational heat stress in the context of climate change, reviews the current global status, and reflects on the health implications, presents an overview of the outcomes and the very important next steps.
Methods Epidemiological evidence from author’s seasonal studies with workers engaged in moderate to heavy labour in ~35 Indian workplaces collected over a 8 year period on occupational heat exposures(n=~3500), self-reported heat-related health symptoms/productivity losses and physiological data(n=~2000) were analysed to understand the level and extent of heat stress impacts.
Results A significant number of workers (~82%) had heat exposures higher than the recommended WBGT (Avg.WBGT of 28.7°C±3.1°C). Workers exposed to chronic high-heat had significant higher odds of adverse-health outcomes (OR=2.43, 95% CI: 1.88 to 3.13, p-value≤0.0001) and productivity losses(OR=1.79, 95% CI: 1.32 to 2.4, p-value=0.0002). Above normal sweat rates, urinary specific gravities, rise in Core Body Temperature and moderate dehydration were common, with compromised renal health prevalence high among exposed workers in certain occupations. Climate Projections show that future temperature rise to impose additional health and productivity risks for workers, especially in hot seasons.
Conclusion Current workplace exposure standards must be revisited and optimised for tropical settings and be consistent with the approach of protecting workers against adverse effects to health. In-depth research investigations on health implications of heat stress are an urgent need. Though reducing workplace heat stress by interventions has multiple benefits, adaptation and mitigation measures including policy changes are imperative to tackle heat stress at workplaces in the Climate Change future.