HeatTracking: Monitoring Heat-Related Symptoms in the Community Through Participatory Self-Reporting
Heatwaves are the deadliest natural disaster in Australia, responsible for more deaths than all other natural disasters combined. Yet existing heat surveillance systems focus almost exclusively on severe outcomes — heat stroke and heat exhaustion documented in emergency departments — missing the far larger population experiencing mild to moderate heat-related symptoms. Our study piloted HeatTracking, a participatory surveillance system designed to capture this hidden burden of heat illness in everyday community settings.
HeatTracking was built on the existing infrastructure of FluTracking Australia, a community-level surveillance network with over 50,000 volunteers. FluTracking respondents in Western Sydney, South-Eastern Sydney, North-Western Melbourne, and South-Eastern Melbourne were invited to enrol. Of 6,184 invitees, 1,197 (19.4%) consented, and together with their household members, the final study population reached 1,735 participants. A weekly online survey was sent for 9 weeks during the 2024/2025 Australian summer (6 January – 3 March 2025).
Key Findings
Between 11.7% and 21.0% of participants reported heat-related health impacts each week. The most commonly reported symptom was sleep difficulty (9.0–16.7%), followed by dizziness or light-headedness (3.8–7.9%). Each week, 6.5%–13.9% of those with symptoms took time off normal duties, and 0.7–3.0% sought care at a pharmacy, medical centre, or hospital.
The most common management strategies were drinking more fluids (65.1%), using air-conditioning (60.8%), and using a fan (57.4%). Participants without air-conditioning at home relied more heavily on fans and water-based cooling strategies.
Factors independently associated with higher odds of heat-related symptoms included:
- Older age and female sex
- Higher apparent temperatures in the area of residence
- Living in rental accommodation
- Spending more hours feeling too hot due to work, exercise, or daily activity
- Prior history of heat-related health impacts
Feasibility and Participant Satisfaction
Retention was high: 93.7% of participants completed five or more of the nine weekly surveys, and 68.1% completed all nine. Participant satisfaction was strong, with 93.1% indicating they would likely participate again and 78.4% saying they would recommend HeatTracking to friends and family.
Qualitative feedback identified eight areas for future improvement, including capturing a broader symptom set (e.g. fatigue, nausea, headache), tracking preventive behaviours, collecting productivity and quality-of-life impacts, and refining location data collection to reduce participant burden.
Implications
This study demonstrates that a participatory surveillance approach to monitoring heat-related health impacts is feasible and can capture population-level data that existing systems miss. Future iterations of HeatTracking should aim to minimise recall bias while expanding the breadth of symptoms, behaviours, and exposures captured. Scaling this approach nationally could provide critical real-time data to guide public health responses during heatwaves.