A systematic review of heat health warning systems: enhancing the framework towards effective health outcomes

This publication covers the design and effectiveness of heat-health warning systems (HHWS) and examines how current approaches can be strengthened to better reduce heat-related morbidity and mortality. Based on a systematic review of scientific studies, it assesses how HHWS define heat-stress thresholds using meteorological variables, climate-epidemiological evidence, personalization, and built-environment factors, and identifies key gaps that limit their precision and public health impact.

The review finds that most existing HHWS rely primarily on temperature-mortality relationships, with limited use of other meteorological variables or direct health outcome data. The findings highlight the need to better integrate climate-epidemiological evidence, including cause-specific mortality and morbidity, as well as local contextual factors. Incorporating characteristics of the built environment and individual vulnerability can further refine how warnings are designed and communicated.