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The health impact of heat

What happens to my body in extreme heat?

When the weather is very hot, the body has to work very hard and produce a lot of sweat to keep itself cool. Under some conditions, sweating just isn’t enough and a person’s body temperature rises rapidly.

Exposure to high temperatures can make existing illnesses seriously worse (for example trigger a heart attack), cause serious permanent injuries (damage to the brain or other vital organs) as a result of untreated heat stroke, and in extreme cases result in death.

What are the signs of heat-related illness?

Signs of heat-related illness include: dizziness, tiredness, irritability, thirst, fainting, muscle pains or cramps, headache, changes in skin colour, rapid pulse, shallow breathing, vomiting and confusion.

During extremely hot weather, it is easy to become dehydrated (lose too much water from your body) or for your body to overheat. If this happens you may develop heat cramps, heat exhaustion or even heatstroke. If you suffer from any chronic health conditions, your condition may become worse during a period of hot weather.

Who is most at risk?

Everyone needs to take care in hot weather but some people are at higher risk of heat illness, especially if they live alone or are socially isolated. These groups include:

  • Older adults
  • Pregnant women
  • Infants and young children
  • People who have a chronic or acute illness
  • People who take certain medications
  • People working outside or in a hot environment
  • People who live alone or are socially isolated

What should I do to manage my heat levels?

Heat waves or long periods of extreme heat can have serious impacts on people's health. Planning ahead and being prepared for extreme heat is important. Remember to:

  • Keep yourself cool
  • Stay hydrated by drinking water
  • Look out for each other
  • Plan ahead for the heat

How should I prepare my home for a heat wave?

It is a good idea to prepare for the heat before it arrives. You can prepare your house or apartment by:

  • If you have air conditioning, set it to cool. If you don’t have air conditioning consider getting a fan.
  • Consider buying cool packs to have in the fridge or freezer to help you cool down if needed.
  • If available, curtains with pale linings help reflect the heat. Avoid dark reflective curtain linings and metal Venetian blinds as they absorb heat and may make rooms hotter.

Heat and bushfire smoke

Is there a link between heat and bushfire smoke?

Hot weather is one contributor to increasing bushfire risk.

What should I do when it’s hot and smoky from bushfires?

On hot, smoky days take precautions to reduce your exposure to high heat and smoke. Stay cool and out of smoky conditions by avoiding vigorous outdoor activity and spending more time indoors with the doors and windows shut. Closing window curtains or blinds can keep the inside of your house cool. If you don’t have access to air conditioning at home, or the smoke is inside your house, spend time in air conditioned indoor venues like cinemas, libraries and shopping centres.

In an emergency, call Triple Zero (000) or go to your nearest hospital emergency department.

Impact on health services

Will the heat affect electricity supply to NSW hospitals?

To ensure all hospitals deliver continuous health services during summer when electrical supply may be affected by extreme heat conditions, NSW Health ensures all facilities comply with the Australian Standards regarding emergency power supply.

All hospitals have emergency backup generators to guarantee there is no disruption to life-saving medical equipment, and areas that require essential power supply.

These generators are routinely tested to confirm they are in working order should they be required if the mains grid is disrupted. These inspections also include a risk assessment to establish mitigations measures should power supply affect air-conditioning systems.

Heatwave information

At what temperature does it become a heatwave?

Three or more days of high maximum and minimum temperatures that are unusual for that location. Heatwaves finish when temperatures fall to more normal levels.

How do I check heatwave levels?

The Bureau of Meteorology operates the Heatwave Service which is a set of maps showing colour-coded heatwave severity for the previous two three-day periods, and the next five three-day periods. Visit: Heatwave Service for Australia

Will I be affected by the heatwave?

You may be affected if the map shows a heatwave is current in your area, or you are close to a heatwave region. If this is the case, you should take precautions to reduce your exposure to high heat and follow advice from NSW Health or your doctor. Check areas affected on the Bureau of Meteorology's website: Heatwave Service for Australia


Is climate change a contributing factor to heatwave events?

Climate projections show that extreme heat events are expected to occur more often and with greater intensity in the future.

Can I drink alcohol and caffeine to rehydrate?

Alcoholic, hot or sugary drinks including tea and coffee can make dehydration worse. During extreme heat, water is recommended as the drink of choice to rehydrate.

Current as at: Wednesday 18 December 2019
Contact page owner: Environmental Health