Spotlight on Heat Health Research at Sydney University

Words and Photos – Marie Geissler

Breaking New Ground in Heat Health
On 10 October 2025, University of Sydney’s Heat and Health Research Centre, hosted FCA journalists at an exclusive in-lab briefing with Professor Ollie Jay, Director of the Thermal Ergonomics Lab. This visit offered a rare opportunity to witness cutting-edge research on human resilience to extreme heat and the life-saving potential of simple cooling strategies.

Inside the Heat Lab
The Sydney University Heat Lab Simulator allows scientists to recreate heatwave conditions from around the world, from blistering dry heat to humid, post-storm environments. Journalists experienced first-hand how these extreme conditions affect the human body and gained insight into Professor Jay’s groundbreaking findings.

Key Findings from Professor Jay’s Research

• Fans Save Lives: In humid conditions, low-cost electric fans were shown to lower core body temperature, reduce cardiac strain, and increase comfort—contradicting long-standing public health advice that discourages fan use above 37°C (99°F).
• Vulnerable Populations Benefit Most: Children, the elderly, and people with chronic health conditions could see significant health benefits from safe fan use during heatwaves.
• Equity and Climate Implications: Fans provide an accessible cooling method for millions who cannot afford or access air-conditioning, while helping reduce climate-impacting energy consumption.

Why This Matters
With heatwaves already causing thousands of deaths globally each year, Professor Jay’s research underscores the urgency of updating public health guidelines. The study highlights the importance of practical, low-energy solutions to protect populations, especially as climate change accelerates extreme heat events.

A Hands-On Experience
Journalists were able to test their own responses in the Heat Lab Simulator, exploring how heat impacts human physiology and occupational conditions. The session offered a vivid perspective on the realities of working and living in extreme temperatures, paired with expert insights from one of the world’s leading heat and health researchers.

Looking Ahead
As Professor Jay notes, “The heat problem is not going away. Our findings show that in many cases, fans are not only safe but effective—and could save lives during extreme heat events.” This research is guiding international public health agencies updated, evidence-based cooling recommendations.

Dr Mella and her colleague Dr Mark Krockenberger also highlighted the escalating impact of climate change. Rising temperatures, more frequent heatwaves, and increasingly dry conditions are contributing to the spread and severity of chlamydia infections, which can move rapidly through stressed populations and exacerbate reproductive decline.

One of Dr Mella’s notable findings has also challenged long-held assumptions in koala biology: koalas do drink water, particularly during periods of drought. She also described their remarkable behavioural adaptations during extreme heat. Koalas have been observed pressing their bodies against smooth-barked tree trunks, which can be several degrees cooler than the surrounding air. In addition, they are capable of allowing their body temperature to rise to around 41°C to reduce water loss through panting. As she explained, “They fluctuate their temperature to conserve the water they so desperately need.” However, she cautioned that these physiological adaptations have limits. Prolonged periods above 40°C, increasingly likely under climate change scenarios, can lead to cellular failure and death.