Introduction

Australia has experienced a number of lethal heatwaves, and hot summers are normal for most parts of the country.1 ,2 However, while there has been a strong research and policy focus to inform and support strategies to minimise harm from hot weather to vulnerable groups at the community level,3 less attention has been paid to the safety of people while they work. Heat-related workplace fatalities have been reported in Australia,4 ,5 and deaths of people of working age occurred in Victoria during a severe heatwave in 2009.6 A study set in Adelaide found the risk of occupational heat illness during heatwave periods to be approximately seven times higher than during non-heatwave periods, over the years 2001–2010.7

Workers, especially those engaged in heavy physical activity in outdoor or non-temperature-regulated indoor locations, face challenges to their health during hot weather as heat generated by muscle activity adds to their heat burden from the environment.8 Excessive heat stress arising from working in hot weather, in conjunction with inadequate replacement of water and electrolytes lost through sweating, can lead to a spectrum of acute heat-related illnesses ranging from heat rashes, cramps and heat exhaustion, to heat stroke, a severe potentially fatal illness requiring urgent medical attention.9 Working in hot weather has also been associated with an increased risk of work-related injury and renal disease.10 ,11

Sensitivity to hot weather is increased by factors that reduce the effectiveness of thermoregulation including dehydration, older age, obesity, skin conditions that limit sweating, heavy or impermeable clothing, chronic disease, some medications, alcohol and recreational drugs.12 ,13 Conversely, acclimatisation to heat and improved fitness increase thermoregulatory efficiency.14 The capacity of individual workers and the workplace to adapt to hot weather will be influenced by workplace …