Stakeholders are warning of the increasing danger heatwaves pose to human health, as northern regions swelter through an unseasonably hot September

A Queensland University of Technology expert has warned Australians to try to stay cool and hydrated, and to check on family and friends – particularly infants, those who may be ill, and the elderly.

Professor Gerard FitzGerald, from QUT’s School of Public Health and Social Work, said heatwaves were the second highest cause of death after pandemics in terms of major threats to public health, and this year they are posing a threat earlier than normal.

“Parts of Queensland, including the south-east are predicted to reach the mid-to-high 30s and even 40 degrees today which is pretty extreme for September,” said Professor FitzGerald, editor of Disaster Health Management: a primer for students and practitioners, published earlier this year.

“People under stress from heat can become quite distressed and alcohol can contribute to dehydration which in turn can lead to aggressive behaviour. If you are having an alcoholic beverage on a hot day then ensure you keep your water intake up as well.

“However, those most badly affected or likely to die during heatwaves are people with chronic diseases including the elderly and those with diabetes, renal failure or cardio or cerebro-vascular disease.

“The signals to be aware of that will alert you your body is dangerously dehydrated include dizziness, nausea, looking flushed, skin not bouncing back, aggression, sleepiness and high temperature.”

The warning comes as researchers write in the Medical Journal of Australia that we need a “better approach” to the prevention and management of the way heatwaves impact health.

Marion G Carey, Mark P Monaghan and Fiona J Stanley highlight that 2016 was the hottest year on record, with climate change caused by human activities raising average temperatures about a degree above levels seen before the Industrial Revolution.

“Heatwaves are becoming hotter, longer and more frequent, and are increasing the risk of bushfires,” they warn.

“The number of record hot days in Australia has doubled in the past 50 years, and marine heatwaves are causing severe coral bleaching in the Great Barrier Reef.

“The recent summer of 2016-17 saw the highest monthly mean temperatures on record for Sydney and Brisbane. On 11 February, the average maximum temperature across New South Wales was 44°C, making it one of the hottest places on earth at the time.”

They write that extreme heat can affect health directly, through heat-related illnesses when the body’s thermoregulatory mechanisms cannot maintain a normal core temperature; or indirectly through exacerbation of existing conditions among vulnerable people.

People who may be disproportionately affected include older people; very young people; people with chronic comorbidities including cardiovascular, respiratory and metabolic disorders; those with cognitive disorders or mental illnesses; and those taking some medications.

“The homeless and socially isolated, people of lower socio-economic status, and those living in poorly adapted urban environments are also at increased risk.”

This week the Where Should All the Trees Go report found that poor and disadvantaged Australian suburbs risk having urban “hotspots” that are more than 10 degrees hotter than greener, wealthier areas.

Carey, Monaghan and Stanley write in the MJA that increases are evident in ambulance and emergency department services, and mortality rates, during heatwaves. They compared a 2009 Melbourne heatwave with the same period in previous years, and showed an almost threefold increase in patients dead on arrival at EDs, and overall, 374 excess deaths.

They write that while addressing climate change is the most important response, more needs to be done in the meantime.

“There is evidence that the adverse health effects of heatwaves may be minimised through effective heat health action plans, which aim to prevent, respond to and manage heat-related risks to health.

“These include not only short term emergency measures but also longer term adaptive responses. Key elements include a heatwave warning system, providing heat health messaging to vulnerable people, primary health care providers reviewing and advising those at risk, activating social networks including outreach and monitoring older and socially isolated people, and timely surveillance of morbidity and mortality.

“A heat health warning system is a crucial component of a heatwave response plan and this service is now provided by the Bureau of Meteorology.”

Urban planning and infrastructure – such as improved public transport – is also key.

The writers single out GPs as a potential source of identifying at-risk patients and educating them about ways to prevent heat illness.

There is limited research measuring the effectiveness of public health interventions for extreme heat and there are many challenges in doing so, they write; though lower mortality has been reported in some locations where such interventions have been attempted.

“Our responsibility is to meet the health threats from heatwaves and other climate-related risks to health with real action on climate change, improved short term disaster responses and better longer term adaptation strategies.

“Extreme heat will otherwise take an increasing toll on the health of Australians, particularly the most vulnerable.”

 

Handling the heat

During last week’s unseasonable heat, 2010 pharmacist of the year and Queenslander Karalyn Huxhagen told the AJP that pharmacists also help keep vulnerable people safer.

“So we’re speaking to people about using oral rehydration solutions, whatever electrolyte solution they like, but at least two servings a day,” she said, adding that vulnerable people may also be at particular risk if they get into hot cars without allowing the vehicle to cool down first.

Meanwhile, QUT’s Prof FitzGerald has offered a list of further suggestions for consumers:

  • Dehydration is the greatest danger from heatwaves. Drink enough water to have relatively clear urine which indicates you are well hydrated.
  • Dry conditions such as we are experiencing are more dangerous than humid conditions in a heatwave because we dehydrate more rapidly as water in our sweat and breath evaporates.
  • Heatwaves can also cause heat stroke which occurs when the body overheats and cannot regulate its temperature.
  • Dehydration can trigger heart attacks or strokes and aggravate existing diseases such as kidney failure.
  • If you are drinking alcohol, match each glass with the same amount of water.
  • Seek cool environments. If you don’t have air-conditioning at home, visit a local shopping centre or cinema. Fans can be helpful and in the current dry conditions, a little water on the skin will help you stay cool.
  • Avoid vigorous exercise and if outdoors, look for shade; wear cool cotton clothing, a hat and sunscreen.
  • Check on relatives and elderly neighbours.
  • Make sure your pets have shade and water.