Climate and heart health

How to protect your heart in extreme weather conditions

Australia’s climate is changing. Over the past several decades we've experienced more extreme temperatures, weather events and air pollution. This can impact the way you live in a number of ways, but did you know that it can also affect your heart health? 

Who is most at risk? 

Extreme temperatures and weather events can cause heart problems in anyone, even in healthy people. They can put stress on your cardiovascular system, regardless of how fit you are, and create physical changes that interfere with your heart’s normal function. However, some people are more vulnerable than others to the effects of extreme temperatures, weather events and pollution. These people include those who are: 

• living with heart disease
• older people
• living with multiple health conditions
• using certain heart or blood pressure medicines
• living in rural and remote areas, as they may be more exposed to extreme temperatures, with less access to healthcare and relief from the heat
• with lower incomes, as poorer housing conditions and limited access to resources can reduce their ability to adapt and cope in extreme heat.

Extreme temperatures 

In Australia, high temperatures are considered a significant risk factor for cardiovascular disease (CVD). This is predicted to escalate as the climate gets warmer. 

In extremely high temperatures, your heart has to work harder to cool your body down. Your heart rate increases, and more blood flows to your skin to help regulate your internal temperature. You can also become dehydrated due to sweating, water loss, or not drinking enough fluids, causing your blood to thicken and putting you at greater risk of heart attack, stroke or heart failure. 

This can lower your blood pressure and reduce blood flow to your heart, increasing your risk of complications like arrhythmia, cardiac arrest and stroke. In fact, in hotter climates like Australia, every 1 °C increase in temperature above 24 °C causes a 3.5% increased risk of heart-related deaths.  

Bushfires

In addition to increasing average temperatures, climate change has caused more frequent bushfires in Australia. Exposure to bushfire smoke is dangerous for everyone, but can be particularly dangerous for people with existing heart problems.  

Bushfire smoke contains tiny particles that can enter your lungs and bloodstream causing inflammation, abnormal heart rhythms, and a greater risk of heart attack and heart failure. Even short-term exposure to bushfire smoke can increase your risk of CVD. 

Air pollution 

Air pollution refers to the tiny, invisible particles and gases circulating in our air, which can harm your heart and lungs when you breathe them in. It’s a significant risk factor for CVD in Australia and is especially harmful for people with existing heart conditions. Long-term exposure to air pollution is estimated to contribute to around 1 in 5 cardiovascular-related deaths worldwide.  

Air pollution exists in both outdoor and indoor environments, with key sources including exhaust fumes from cars and vehicles, fires, farming and waste burning, industrial manufacturing, secondhand cigarette smoke, dust, dampness and mould, and chemical cleaning products. 

Over time, exposure to air pollution can cause your blood vessels to narrow and harden, increasing your risk of blot clots, raising blood pressure, and resulting in abnormal heart rhythms. This can put you at greater risk of CVD including heart attack, coronary heart disease, cardiac arrest, heart failure and stroke. 

How to help protect your heart 

Stay hydrated

• Drink water consistently in extremely hot and cold temperatures, even if you’re not thirsty. Dehydration can occur even in cold temperatures! If you’re struggling to drink enough water when cold, try herbal teas and warm broths. 
• Avoid alcohol, sugary drinks and caffeine, as these can be dehydrating.
• Speak to your general practitioner (GP) or clinic if you’re using heart or blood pressure medicines, as some medicines can increase your risk of dehydration and impact how your body responds to extreme temperatures. 
• If you’re living with heart failure or another condition that requires you to restrict and monitor your fluids, it’s important to closely track and maintain your fluid levels during extreme temperatures. Speak to your GP or clinic for advice and support if you’d like help with managing your fluid intake.

Manage your temperature

• During extreme heat events, avoid strenuous activity during the hottest hours of the day. Stay indoors with your curtains and doors closed to keep heat out, use an electric fan or air conditioning if you can, or head to your local shopping centre, library, or public facility with air conditioning.
• In very cold temperatures, try to maintain a warm, comfortable temperature indoors, and layer up in clothing made from fibres that retain warmth, like merino wool. Ensure your hands, feet and head are protected and warm when you’re heading outdoors. Choose warming, comforting foods such as soup, curries and stews.

Minimise exposure

• Stay informed of bushfire warnings, check the air quality in your area, and plan ahead when you can. Stock up on food, medicines and other supplies to reduce the amount of time you need to spend outside.
• If there are bushfires in your area, stay indoors as much as possible (unless it’s unsafe or you’ve been asked to evacuate) and avoid exercising or walking outside, especially if the air quality is poor. You can also ask your GP, clinic or pharmacist about using an N95 mask if you’re concerned about air pollution exposure.

• Spend time in areas with lower pollution levels like parks, especially if you're walking, running or cycling. Avoid high-pollution areas, like busy roads or factories, especially if you live with an existing heart condition.
• Walk or bike ride instead of driving, to help reduce air pollution.
• Use an air purifier in your home and set your air conditioner to recycle mode to help reduce indoor air pollution, and avoid indoor fires for cooking or warmth.
• Stop smoking and avoid exposure to secondhand smoke (from cigarettes and vapes). 

Stay connected

• In the case of extreme weather events, check on those around you, particularly older people, neighbours and family members who may need some extra support.
• If you’re experiencing dizziness, nausea, confusion, chest pain, muscle pain/cramps, headaches, vomiting or shortness of breath, seek medical assistance. If your symptoms are ever or sudden, call Triple Zero (000).

Why this matters 

Climate change is a major risk factor for heart disease, just like smoking, poor diet, high blood pressure, high cholesterol, and a sedentary lifestyle. You actively make changes to manage other risk factors and protect your heart, so it’s important to do the same when it comes to climate change. 

By implementing strategies to help you stay safe during extreme weather events and temperatures, you can proactively reduce your risk of CVD and protect your heart health. 

Learn more about how air pollution, heat waves and bushfires can affect your heart health and CVD risk here.