Hot of Not: Physiological versus Meteorological Heatwaves-Support for a Mean Temperature Threshold

Area of Science:

• Environmental Health
• Public Health Surveillance
• Emergency Medicine

Background:

• Rising global temperatures necessitate improved public health strategies for heat-related illnesses.
• Existing heat warning systems may not adequately capture local environmental heat impacts on emergency department (ED) presentations.
• Canberra, Australia experiences distinct summer climate patterns requiring localized heat threshold analysis.

Purpose of the Study:

• To evaluate a revised heat warning threshold's effectiveness in predicting ED heat-related presentations.
• To establish a correlation between mean temperature thresholds and increased heat-related illness visits.
• To identify a specific temperature threshold indicating a significant public health risk in Canberra.

Main Methods:

• Retrospective analysis of ED triage records and diagnoses for heat-related illnesses during summer periods (2013-2016).
• Medical record review to confirm environmental heat as the cause of presentation.
• Comparison of confirmed heat-related presentations with a novel mean threshold temperature formula incorporating daily and consecutive mean temperatures.

Main Results:

• Heat-related ED presentations increased when the mean threshold temperature reached 25°C (77°F).
• Significant increases in heat-related presentations were observed when the mean threshold temperature reached 30°C (86°F).
• The study identified a 30°C mean threshold as a critical indicator for public health action.

Conclusions:

• A revised mean temperature threshold effectively predicts increases in ED heat-related presentations.
• A 30°C mean threshold temperature serves as a relevant public health warning for environmental heat threats.
• This finding supports the implementation of localized, temperature-based heat warning systems to mitigate heat-related morbidity.