LAUSR

Background Predicted rise in global mean temperatures of 2°C–3°C and much larger increases in some regions due to Climate Change is expected to impact workers’ health because of physiological limits due to the Wet Bulb Globe Temperature (WBGT). Such temperatures rise implies increasingly large increases in regions where outdoor and indoor work is restricted due to physiological decrements and reduced work capacity. Aim We compare the potential health and productivity risks for indoor and outdoor workers in select Indian workplaces. Methods The study population was a random sample of ∼1300 outdoor and indoor workers from various occupations in Indian workplaces. We conducted seasonal WBGT exposures, quantitative physiological heat-strain measurements and captured self-reported health symptoms through questionnaires. The risk definition included symptoms of heat-strain, self-reported heat-illness, and reduced work capacity/productivity loss. Results WBGT exceeded threshold limit values for moderate/heavy work for 73% outdoor workers (28.9°C±2.4°C) and 67% indoor workers (28.8°C±3.5°C). Heat stress and heat-strain indicators were significantly associated (p=0.0001) and outdoor workers had 2.2 times greater risk of heat-strain during hot seasons (95% CI: 1.695–2.937). Compared to indoor workers, the outdoor workers ran a higher risk of self-reported health decrements (OR: 6.4; 95% CI: 3.884–10.350; p=0.0001), dehydration (OR: 3.0; 95% CI: 2.352–3.999) and productivity losses (OR: 8.0; 95% CI: 4.911–13.382). In select occupations, while indoor workers exposed to chronic high-heat had a higher percentage of kidney stones (9%), the outdoor workers with long years of heat exposures had the higher risk of reduced kidney function (14%) due to repeated dehydration, volume depletion, and Acute Kidney Injury. Conclusion We discuss implications for workers’ health and productivity as climate modeling shows seriously increasing outdoor and indoor heat problems without suitable control measures for cooling. Strong protective labor policies and research are imperative to avoid serious health impacts and to maintain productivity.