Doctors warn there are biological limits to temperatures we can survive, and exposure to extreme heat can provoke a heart attack

Australia’s southern states are scorching in extreme heat that could break temperature records in Victoria and South Australia on Tuesday.

At Ouyen and Mildura in north-west Victoria, temperatures of 49C were forecast for Tuesday afternoon. If reached, they would break the state’s all-time temperature record of 48.8C, set in Hopetoun on Black Saturday in 2009. By 1pm, temperatures of 46.2C in Ouyen and 44.8C in Mildura had been recorded.

At Ouyen and Mildura in north-west Victoria, temperatures of 49C were forecast for Tuesday afternoon. If reached, they would break the state’s all-time temperature record of 48.8C, set in Hopetoun on Black Saturday in 2009. By 1pm, temperatures of 46.2C in Ouyen and 44.8C in Mildura had been recorded.

In Adelaide, the mercury hit 40C before 9.30am on Tuesday, after overnight lows of 35C, BoM observations showed.

Extreme heat is the most common cause of weather-related hospitalisations in Australia, and kills more people than all other natural hazards combined. What does exposure to extreme heat – such as a temperature of 49C – do to the body?

  • Dave.@aussie.zoneEnglish
    67·
    2 days ago

    I’ve worked in mines in the desert in South Australia where temps semi regularly hit 46-47 degrees.

    It’s OK (ish) because the humidity is low. But you can drink a litre an hour all day (11+ hours) and not need to pee. All that water goes somewhere.

    The underground workings are often more dangerous, with lower temperatures but higher humidity. Once wet bulb temps get above 34 degrees underground personnel need to retreat from the area and the only work that can be done there then is work to fix the ventilation.

    There’s heat stress meters that measure wet and dry bulb temperatures and airflow, and can basically compute cooling power in watts. Not enough cooling power -> everyone out.

    • stoy@lemmy.zipEnglish
      35·
      2 days ago

      I can only imagine, as I sit on the Stockholm metro with cold and damp feet after walking through snow and some slush to get to the bus earlier.

      I am happy to hear that you have rules and regulations for these eventualities.

      • T00l_shed@lemmy.worldEnglish
        1·
        8 hours ago

        Now, please correct me if I am wrong, but would drinking cold stuff balance out the temperature difference? Like say it’s 40c wet bulb, but you have access to cold water to drink, would that work?

        • Soggy@lemmy.worldEnglish
          1·
          1 hour ago

          You couldn’t physically drink enough water. Math is not my strong suit but this seems pretty straightforward.

          It takes one calorie to raise the temperature of 1 gram of water by 1 degree Celsius, by definition. Plugging in some numbers (a liter of water starting at a very frosty 1 C) takes almost 40 kilocalories or about 160 kiloJoules of energy. That’s like half of your “simply existing” calories per hour, so you’d need to consume 2 liters of ice-cold water every hour (and excrete every gram of it to 40, which you aren’t doing with your living body) just to break even.

          It gets more complicated when you factor in evaporative cooling and I already said I’m not a math-man but the environmental factor is simply too strong for biology.