Workplace heat stress, health and productivity – an increasing challenge for low and middle-income countries during climate change

TLDR

Global climate change is raising temperatures and heat exposure worldwide, and the Wet Bulb Globe Temperature (WBGT) is a widely used metric to assess occupational heat risk. The study aims to evaluate how rising heat from climate change affects occupational health and work capacity. The authors review thermal physiology, occupational heat guidelines, and heat exposure indices, then use WBGT to estimate the proportion of a working hour a worker can sustain and the required rest, deriving work‑capacity estimates for various heat levels and work intensities. Workers in hot seasons already experience heat beyond physiological limits, and work capacity falls sharply when WBGT exceeds 26–30 °C, indicating climate change will reduce productivity and hinder development in affected countries.

Abstract

Background: Global climate change is already increasing the average temperature and direct heat exposure in many places around the world. Objectives: To assess the potential impact on occupational health and work capacity for people exposed at work to increasing heat due to climate change. Design: A brief review of basic thermal physiology mechanisms, occupational heat exposure guidelines and heat exposure changes in selected cities. Results: In countries with very hot seasons, workers are already affected by working environments hotter than that with which human physiological mechanisms can cope. To protect workers from excessive heat, a number of heat exposure indices have been developed. One that is commonly used in occupational health is the Wet Bulb Globe Temperature (WBGT). We use WBGT to illustrate assessing the proportion of a working hour during which a worker can sustain work and the proportion of that same working hour that (s)he needs to rest to cool the body down and maintain core body temperature below 38°C. Using this proportion a 'work capacity' estimate was calculated for selected heat exposure levels and work intensity levels. The work capacity rapidly reduces as the WBGT exceeds 26–30°C and this can be used to estimate the impact of increasing heat exposure as a result of climate change in tropical countries. Conclusions: One result of climate change is a reduced work capacity in heat-exposed jobs and greater difficulty in achieving economic and social development in the countries affected by this somewhat neglected impact of climate change.