Hot homes were linked to greater heart strain in older Australians, a Griffith University team found. The team tracked 47 adults aged 65 and over in South East Queensland from December 2024 to March 2025.
The university said heart rate rose more steeply once rooms reached 26°C. The study appears in the peer-reviewed journal Temperature. Griffith described field research that monitored people under real-world living conditions.
Hot homes and changes in heart rate
According to Griffith, the team tracked heart rate, movement, room temperature and humidity, with over 64,000 hours of data. Researcher Aaron Bach described the rise at or above 26°C. Heart rate increased 1.3 beats per minute for each extra degree Celsius, he said.
That is a change in the rate of increase, not a doubling of anyone’s heart rate. Lead author Fergus O’Connor said strain could persist for hours after heat exposure. Bach said room temperature, rather than humidity, was the main factor linked to more strain.
A threshold for action, not a guarantee
Health Canada recommends keeping rooms no warmer than 26°C to help protect people aged 60 and over. The agency based that advice on a review of studies, both in labs and in homes.
However, Health Canada says that limit may not protect every older person. Those with several health conditions or severe frailty may need more protection. It describes the threshold as a point for action to protect health, rather than a target for comfort.
The agency says to avoid long stays in hot homes at 26°C to 31°C where possible, especially overnight. Its guidance notes limits in the evidence, including small samples and gaps in knowledge about risks over several days.
The Griffith researchers also called for better housing design, affordable cooling and heat-health messages for those most at risk. Health Canada says more research is needed to test how well indoor heat limits protect older adults over several days.
Sources: Health Canada, Griffith University, Temperature
