Weather

Not only can extremes of heat and cold trigger people’s asthma, even sudden changes in temperature can cause symptoms to flare up.

On this page:

• Cold weather
• Changes in weather
• Thunderstorms
• Hot weather 

Cold weather

When it gets colder, you may notice that your asthma symptoms get worse. If this happens to you, you might dread winter every year. Read on to find out how to manage this common asthma trigger.

What can I do if my asthma is triggered by cold air?

Keep taking your regular preventer inhaler, so you’re less likely to get symptoms

Carry your reliever inhaler with you at all times, so you’re ready if symptoms do come on.

Use a written asthma action plan, so you know what to do if cold weather sets off your asthma symptoms

Go for regular asthma reviews. This will help ensure you have the right medicine and pick up on any signs you may be at risk of an asthma attack over winter.

Before you head out in the cold, try wrapping a scarf loosely around your nose and mouth. This stops your airways getting a shock of cold air, which can trigger asthma symptoms.

You could also try breathing in through your nose instead of your mouth, if you can, as this also warms up the air as you breathe it in.

Why does cold weather make my asthma worse?

When it’s cold, the air is colder and drier 

Breathing in dry, cold air irritates your airways. Your lungs then react to this by becoming tighter and this makes it more difficult to breathe.

Our bodies are designed to respond to changes in air temperature. However, some people are more sensitive to changes in temperature and may have a stronger reaction, which includes asthma symptoms that are set off by cold air. The good news is, your asthma is less likely to be triggered by cold weather if it’s well controlled.

You can also help yourself by trying to breathe through your nose more, rather than just your mouth. This is because when you breathe through your nose, cold air is warmed up by passing through your nose, throat and then your upper airways. If you just breathe through your mouth, this warming up process doesn’t happen, which means the cold air dries out the moisture in your lungs.

Cold air makes you produce more mucus

When it’s cold, you might produce more mucus than you normally would.

This is because when cold air enters your nose, the vessels in your nasal cavity get bigger and congested, which causes more mucus to be produced. This extra mucus is produced because your body is trying to create perfect conditions, by adding warmth and humidity, while also filtering the air that’s going into your body. This extra mucus is why you can get a runny nose in winter.

Mucus that you cough up from your lungs is called phlegm and coughing up more of it can be a sign that your airways are inflamed. We’ve got more advice on what you can do about this on our phlegm, mucus and asthma page.  

Cold weather brings colds and flu

Your body can also produce thicker mucus when you have a virus, such as a cold or the flu. These are more common during the colder months and are a top trigger for people with asthma - 75% of people with asthma say colds and flu set off their symptoms.

Cold weather forces us indoors 

When it’s cold, you’re also more likely to be indoors more, which means you’re more exposed to lots of indoor triggers. These include:

• dust mites
• mould and damp
• pet hair
• certain cleaning products
• cigarette smoke.

However, there are lots of things you can do to help keep these at bay, such as opening windows, using extractor fans and not using aerosols or sprays. You can find out more about ways to protect yourself on our indoor triggers page. 

How can I look after my child’s asthma when it’s cold?

Asthma nurse specialist Debby Waddell gives her 3 top tips:

1. “Give your child a scarf to wear scarf loosely over their nose and mouth. It warms up the air they’re breathing in, so they’re less likely to get asthma symptoms.”
   
   
2. “Talk to teachers about your child’s asthma triggers, including cold weather. Make sure your give the school a named spare reliever inhaler and spacer for your child to use if their asthma symptoms come on at playtime or during PE.”
   
   
3. “Most important of all, stick to your child’s preventer routine, and follow their written asthma action plan, so you’re staying on top of their asthma during the winter months. If their asthma is well controlled, your child is less likely to react to cold weather. And don’t forget to carry their reliever inhaler with you all the time, so you can act quickly if cold weather triggers their asthma.”