How Winter Can Make Asthma Worse

Asthma sufferers often find their symptoms become worse during the winter months. But why is that the case? And what can you do about it? We reveal all below.

Published: Thursday 08 October 2020


asthma in winter

For many asthma sufferers, the condition is characterised by symptoms that get worse under certain conditions. People with occupational asthma, for example, find their symptoms are triggered by substances in the workplace, such as gas, dust and chemical fumes. Allergy-induced asthma tends to become worse when sufferers are exposed to airborne substances such as pollen, mould and pet dander. In many instances, however, asthma symptoms can also become worse simply because of a change in the weather.

When the winter months roll around, a number of conditions emerge that may exacerbate asthma symptoms. It isn’t just the temperature, either: dry air, increased mucus production and a higher likelihood of being sick are all winter-related problems that leave people with asthma at risk of more attacks. There’s no question that winter can be difficult for asthma sufferers. But there are steps that can be taken to keep yourself safe and your symptoms under control.

Does cold weather actually make you sicker?

It seems almost intuitive that winter could make asthma symptoms worse. After all, winter tends to be when people get sick. People in the UK tend to get the flu during the coldest months of the year. December, January and February are the months when flu cases begin to peak, but outbreaks can begin as early as October. If you feel like people get sicker in winter, you’re not wrong. According to experts, there are a number of reasons people are more likely to get sick when the weather gets cold.

First, there’s the actual weather. When the temperature gets really hot in the summer, it becomes less hospitable for viruses to thrive. In colder temperatures, however, viruses tend to live a lot longer, which makes winter the perfect season for them to spread.

The second reason is related to a lack of humidity. When people transmit viruses to one another, they’re usually standing three feet apart on average. This is called the ‘breathing zone’. In warmer, humid conditions, viruses have a lot more trouble covering this distance because of the small amount of moisture in the air. When the temperature drops, however, that moisture evaporates. This helps the virus stay in the air for sufficient time for the next person to breathe it in.

The third reason people tend to get sicker in winter is related to human behaviour. When human beings get cold, they’ll usually want to go somewhere warm. When we’re out and about, this’ll often mean heading into a nearby cafe or pub to sit down and enjoy the central heating. But this means spending more time in enclosed spaces, in close proximity to others, with more face-to-face contact - making it easier for viruses to spread.

So what about asthma?

Of course, asthma isn’t a virus and therefore can’t be spread. But much of the conditions that help viruses spread in winter can make asthma symptoms worse as well. According to a 2014 study carried out in China, hospital admissions for asthma increase significantly during the winter months. And other research carried out in Finland found that up to 82% of asthma sufferers experience difficulty breathing when they exercise during winter. The evidence overwhelmingly shows that winter is especially hard for asthma sufferers. But why is this the case?

Like sickness in winter more generally, one of the issues is the air. When the temperature drops, humidity often does as well. When you breathe in dry air, the thin layer of fluid that lines your airways evaporates quicker than it can be replaced. In non-asthma sufferers, this can cause mild discomfort. In people with asthma, however, the airways are already inflamed - meaning cold air can make it worse.

The other problem with cold air is that it causes the airways to produce a substance called histamine. In normal circumstances, histamine is actually quite a useful chemical. It tells you you’re allergic to something in the environment, or something you’ve consumed, and causes symptoms that let you know to stay away from that thing in the future. But for asthma sufferers, histamine often triggers wheezing and other troublesome symptoms.

It’s just dry air that’s the problem, then?

Unfortunately not. While the air tends to be dry in the south in winter months, in the north of the UK it’s usually a lot wetter - leaving indoor environments at risk of becoming damp and mouldy. When mould begins to grow in areas of your home, it releases spores that can cause allergy symptoms. For people with asthma, inhaling mould fragments can make the airwaves more inflamed, causing nasal congestion, wheezing, tightness in the chest and irritation in the throat. If you have asthma, this is why it’s really important to investigate and remove mould in your home.

In addition to the humidity (or lack thereof), the other thing asthma sufferers need to watch out for is increased mucus. In normal circumstances, mucus plays an important role in keeping the airways healthy by catching and removing unhealthy particles from the body. In winter, however, the mucus your body produces becomes thicker, which can increase the likelihood of a cold, infection or other respiratory illness. Respiratory illnesses usually exacerbate asthma symptoms.


asthma during the winter

What can I do to make winter easier?

The first and most important thing you must do is try to get your asthma under control before winter starts. For people with more severe forms of asthma, this is much easier said than done. But by developing an asthma action plan with your GP, you’ll be better equipped to keep on top of your symptoms and know what to do when they flare up or an attack happens.

The second thing you can do is keep any medication you use with you at all times. For most asthma sufferers, this means any inhalers you have been prescribed. Your preventer inhaler will help keep your symptoms at bay through everyday use, while your rescue or reliever inhaler can be used when your symptoms flare up suddenly and quickly, such as during an asthma attack. People with more severe forms of asthma may also take oral medication for asthma, which you should remember to take at the direction of your GP or specialist.

In addition to remembering your medication, there are a number of lifestyle adjustments you can make in order to make the winter months easier. The first is to try and stay indoors when the temperature drops really low, around -10°C. These temperatures are very rare in the UK, but not unheard of. When you are outside, the second thing you can do is cover your nose and mouth with a scarf. This’ll help warm up air as you breathe it in.

Other tips to prevent asthma attacks in winter include:

  • Drinking extra fluids to keep the mucus in the airways thinner and easier to remove
  • Avoiding people who appear to be sick
  • Getting your flu jab in the autumn
  • Vacuuming and dusting your home regularly to remove indoor allergens
  • Putting your bed sheets on a hot wash regularly to remove dust mites

If you’re planning on exercising in the cold weather during winter, your doctor may advise that you protect yourself from an asthma attack by using your inhaler 15 to 30 minutes before you start your workout. You should also carry your inhaler as you exercise in case you have an attack.

Harry Walker

Authored by Harry Walker

Patient Care Specialist


After graduating with a degree in Journalism at City, University of London, Harry joined the Pharmica team as a Patient Care Specialist and content writer.

In addition to helping in the dispensary, Harry consults with our in-house pharmacists to produce engaging, informative and expert content for our patients.

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