Heart attacks to premature births: Experts are sounding the alarm on Melbourne’s next hot summer

October 21, 2026 — 4:07pmAs another El Nino summer approaches, health experts are raising the alarm over the potentially fatal consequences of higher temperatures and an increased number of hot days expected around the state.Mounting research showing soaring temperatures can increase rates of stillbirth and premature birth, trigger heart attacks, worsen mental health and exacerbate chronic illnesses comes amid warnings that Victorian emergency departments remain severely underprepared for a surge in heatwaves that are forecast to lead to record-shattering death tolls.The sun rises over Melbourne on a hot morning last year.Jason SouthAs part of this week’s Melbourne Assembly civic forum, The Age has been exploring big ideas for the future of the city, including how infrastructure and housing can be transformed to protect residents from the rise in dangerously high temperatures.Professor Ollie Jay, academic director of the Heat and Health Research Centre at the University of Sydney, said extreme heat cost the Australian economy more than $6 billion in lost productivity every year.“Basically, we’ve got this hazard, which is extreme heat and chronic hot weather that is growing undeniably in Australia,” Jay says.“On top of that, you’ve also got a shift in the population where we have a progressively ageing population, and we’ve got an increased prevalence of chronic diseases like cardiovascular disease and kidney disease.”A growing body of research has laid bare the implications of extreme heat on ageing populations, with a landmark study published in The Lancet Planetary Health in August warning the impacts of heatwaves on people aged 60 and over have been underestimated.Researchers found people in this group face an increase in serious health risks directly linked to rising temperatures, and will bear the brunt of increasingly frequent spells of extreme heat.But it’s not just the heat. Rising humidity also hinders sweat from evaporating, which is the body’s primary physiological mechanism to keep cool.Wind can also affect human thermal states, and direct sun exposure can make an environment feel at least 15 degrees hotter than the official shade temperature reading.“What most people don’t realise is that official temperatures are recorded in the shade,” Jay says.Protecting people from rising extreme heat requires urgent action now, he says, including implementing targeted building and landscape interventions – such as external shutters and reflective roofs – to reduce heat risk.As part of their work, Jay and a team of researchers have reviewed global literature to evaluate over 70 cooling interventions, grading more than 20 building-level strategies based on cost, effectiveness, and scientific evidence.Among the top interventions measured by effectiveness are air conditioning; street trees and urban canopies; outdoor shade structures such as arcades; and reflective roofs (also known as cool roofs) designed to bounce back more sunlight and absorb less heat than standard dark roofs.Jay says that among the greatest challenges for a city like Melbourne is tackling the urban heat island effect – a phenomenon created by poorly designed buildings, roads and footpaths, which can make temperatures vary by as much as 6 degrees across different parts of the city, particularly in fast-growing suburbs.Researchers Dr Sarah Robertson (left) and Dr Rebecca Olive at RMIT University’s Centre for Urban Research.Chris HopkinsExtreme heat is a conundrum that Dr Sarah Robertson, a research fellow at RMIT University’s Centre for Urban Research, has dedicated years to, as she examines ways to make climate resilient and safe housing.Robertson says one of the biggest day-to-day issues is much of Victoria’s existing housing was built before the introduction of energy efficiency and thermal performance standards came in.“We need to focus on improving the quality of our existing housing so it’s thermally comfortable, energy efficient, and affordable for people,” she says, adding that existing housing should be retrofitted or upgraded.Robertson also says the introduction of minimum standards for rental properties, which will come into effect from next year, will be a catalyst for change.“It means for the first time, rental properties have to have ceiling insulation [and] be draft proof, so gaps and around doors and windows sealed up, and have fixed cooling in the living room installed at the point of lease or sale,” she says.Robertson’s colleague, research fellow Dr Rebecca Olive, has focused her attention on outdoor public spaces and “cooling commons”, examining how swimmable urban waterways and shade can protect communities from extreme heat while also keeping people socially connected.“Often we’re told in extreme heat to stay indoors, pull down the blinds, and stay cool ... but this creates great inequities and social isolation, which can link directly to heat-related fatalities,” she says.Olive says many local outdoor pools are deteriorating and have costly leaks, forcing councils into difficult financial decisions and highlighting the urgent need for government funding to upgrade or shade these vital community spaces.Olive has also joined four Melbourne councils in a united push to make the Yarra River safe and clean enough for public swimming by 2050.The government’s recently announced plan to plant 100,000 trees across Melbourne in suburbs where exposure to heat is higher was welcomed by Robertson and Olive.Some of the biggest projects will include more than 15,000 trees in Bayview Park in Narre Warren North, and 14,000 trees at Cranwell Park in Braybrook – a move aimed at improving outdoor community spaces.New research commissioned by Bupa and undertaken by the RedBridge Group found nearly three-quarters of Australians experienced the negative health effects of extreme heat over the past year, emotional and psychological stress being ranked as the single largest health threat. Nearly four in five respondents said hot temperatures were affecting their sleep quality.Despite 98 per cent of households among the 3000 people surveyed saying they had home cooling, about three-quarters said they were forced to limit its use due to rising electricity costs.Start the day with a summary of the day’s most important and interesting stories, analysis and insights. Sign up for our Morning Edition newsletter.From our partners