Heat-Related Mortality

Excessive heat is an environmental and occupational hazard for human health. This chapter reviews current epidemiological evidence of the determinants of heat-related mortality and morbidity in high-income populations in temperate climate zones. Heat-related mortality is found in all populations studied, and population sensitivity to heat (such as the temperature at which heat risk increases) is determined, in part, from the local climate, reflecting adaptation at the population level. Several factors increase individual susceptibility to heat-related mortality, including being elderly and having a chronic illness or disability. Factors that determine exposures to high indoor temperatures depend on housing characteristics and behavior. The role of urban (outdoor) factors in determining individual risks is less well understood. In future decades, the population at risk of heat-related mortality will increase due to the expansion of the elderly population, who are at higher risk. Exposures to high outdoor temperatures may also increase from urbanization (intensification of the urban heat island effect) and climate change from greenhouse gas emissions, aerosols, and land use change. Strategies to reduce heat-related mortality include heat health warning systems and interventions to modify the built environment to reduce indoor and outdoor temperatures.