Background Drowning is a significant cause of injury and death, impacted by environmental conditions. In Australia, drowning risk peaks in summer, yet the impact of heat adaptive behaviours involving water (i.e., swimming) and drowning have not been explored.
Methods Drowning deaths (ICD-10 coded: unintentional, intentional, water transport or undetermined) in Queensland, Australia, between 2010/11 and 2018/19 (nine financial years), were matched to temperature data from the Bureau of Meteorology. Heatwave was defined using Excess Heat Factor, which captures heatwave intensity based on a 3-day daily average temperature compared to the long-term average. Using a case-crossover approach, the number of deaths that occurred on heatwave days were compared with number of deaths that occurred on non-heatwave days on the same day in a calendar year.
Results 576 drowning deaths during the study period (74.8% male; 67.4% unintentional drowning). Risk of fatal drowning was 18% higher on a heatwave day compared to non-heatwave days. This varied by drowning type, with a 24% higher risk of unintentional drowning, compared to 12% higher risk for intentional drowning. Risk of water transport drowning was lower during heatwave.
Conclusion Risk of drowning increases during a heatwave, with that risk greatest for unintentional drowning.
Learning Outcomes These preliminary insights into the link between heatwaves and drowning highlight the need for safe heat adaptive aquatic behaviour. With heatwave frequency, intensity and duration predicted to increase this is likely to impact drowning numbers, highlighting the need for climate action and innovative drowning prevention measures, including quick-to-press water safety messages.