Healthy in the heat

Hot weather and asthma

If you have a respiratory condition such as asthma or hay fever or other chronic respiratory illnesses, it is essential to be prepared for peak summer temperatures.

Extreme temperatures increase the risk of asthma hospital admissions, asthma symptoms, deterioration in lung function and airway inflammation.

Extreme temperature is an independent predictor of asthma exacerbations, exposure to extreme temperatures may lead to the narrowing of the airways (bronchoconstriction) and an increase in inflammatory response and trigger airway hyper-reactivity.

Everyone’s asthma is different. Some people get asthma symptoms in hot humid air, while others are affected by hot dry air. Many people find extreme changes in the weather to be their biggest weather trigger – especially moving from a hot humid day outside into a cool building.

Stay alert for the usual signs that your asthma may be flaring up:

  • wheezing
  • sneezing
  • coughing
  • chest tightness.

Asthma symptoms caused by heat may be different from asthma symptoms you’re used to experiencing. For example, you may typically experience wheezing or coughing with your asthma, but you might have chest tightness due to the heat. 

Follow our top tips to help minimise asthma and allergy symptoms during these hotter periods.

Stay hydrated

Dehydration can play a role in asthma and allergies flare-ups, so it’s important to drink plenty of water throughout the day to stay hydrated and minimise your symptoms where possible.

Keep cool

  • Store your asthma medications somewhere safe from heat. Avoid keeping your puffer or reliever in your car or near a sunny window. 
  • Avoid going out in the extreme heat. 
  • Opt for exercising indoors on extreme heat days. Swap an outdoor run for a gym session or swim. 
  • Beat the heat by going to an air-conditioned shopping centre, cinema or library. 
  • If your house isn’t air-conditioned, use a portable fan to keep cool. This can work better if you close windows and doors and try to keep one room cool.

Plan your day, avoid the triggers you can control

  • Consider staying indoors or avoiding the outdoors, as hot weather can lead to higher levels of pollutants and pollens in the air.
  • Be aware that bushfire smoke, high pollen days, increased air pollution and higher ozone levels can trigger asthma symptoms.  
  • Keep windows closed and minimise outdoor activity.
  • Visit pollenforecast.com.au and plan ahead.
  • If your asthma symptoms start, act promptly to prevent a severe asthma attack.

Create a healthy indoor environment  

During extreme heat conditions, humidity can make hot weather conditions feel even hotter. It is harder for the body to cool down and release heat in a humid environment than in a dry climate.

Indoor humidity levels in the home can play an important role in your health, particularly when asthma and/or allergies are present. Higher levels of humidity in your home can provide an environment for two undesirable triggers – dust mites and mould. 

There are a number of products on the market that can help to control indoor humidity including air-conditioners and dehumidifiers. Learn more in our Indoor Humidity factsheet.

Take preventive action 

Be aware of how you’re feeling. If your asthma symptoms start, act quickly to stop it turning into an asthma attack. 

  • You should not put up with worsening symptoms during the hot and humid weather. If you’re having breathing difficulty and finding that it’s interfering with your normal activity, it’s important that you seek medical help. 
  • Ensure your medication is accessible and up to date. It’s easy to get caught off guard with expired medication or find yourself without immediate access to your medications. 
  • Ensure you have an up to date written asthma action plan and that you are taking your medication as prescribed by your doctor.

First Aid for Asthma

If extreme heat or humidity triggers your asthma:

  • Follow your personal written asthma action plan
  • If you don’t have an action plan, take 4 separate puffs of a blue/grey reliever via a spacer
  • If the symptoms aren’t going away or are getting worse, then follow the steps in First Aid for Asthma

First Aid for Asthma chart tailored to combination inhalers

The new First Aid for Asthma chart is based on combination inhalers with Formoterol (Symbicort, Fostair, DuoResp, BiResp) and outlines how to use one of these inhalers if this is the person’s usual reliever. It is designed for patients using a combination preventer and reliever medication that uses formoterol as the reliever. 

First Aid for Asthma 12+ and the First Aid for Asthma Children Under 12 charts can be downloaded from our website: nationalasthma.org.au.


It is important to note that information contained in this brochure is not intended to replace professional medical advice. Any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. 

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