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It's Almost Winter. Here's How Cold Weather Affects Your Breathing

Cold weather can lead to runny noses, and not just because of flu season.

Person in winter snow with a cloud of visible breath.
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After a long, hot summer, colder air may feel nice, especially when you're exercising outdoors. But the colder it gets, the more of a bite it can bring when you breathe.

When you feel that cold air sting your lungs, you may wonder how cold weather affects your breathing. In most cases, it's just a little burn that passes as you adjust to the cold temperatures. However, for people with certain lung conditions, such as asthma, cold air can present a greater risk. Let's look at what's happening when you breathe cold air and what you can do to stay safe if it causes problems for you.

Cold air is dry air

White sheets blow on a clothesline against a blue sky.
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The issue with cold air isn't necessarily the cold itself. In fact, our lungs seem hardy enough to handle sub-zero temperatures -- just ask any athlete who trains in harsh winter conditions up north. 

The larger problem is that cold air holds much less moisture than warm air. And that dry air can cause breathing difficulties if you're prone to respiratory issues. Even when you're not outside, the dry air in your home, which has been heated by a furnace or boiler, can dry out the mucus in your sinuses, making it easier for infections to take root.

For anyone with asthma, COPD or other lung troubles, that cold, dry air can irritate the airways and cause respiratory symptoms such as coughing, wheezing and shortness of breath.

Cold air means more mucus

Person in winter coat blows their nose with a tissue.
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When your mucus dries out under cool, dry conditions, your body may overcompensate by producing even more mucus. As the cold air enters your nose, it causes the blood vessels to expand, which stimulates more mucus production. That's why you often have a runny nose when you come in from the cold.

Again, mucus serves an important function in preventing infections, filtering your airways, and keeping your nasal cavity and lungs moist. It's a natural defense, but it can increase congestion and worsen other symptoms if you have chronic breathing problems.

Flu season doesn't help

Several flu items, including tissues, tea and medicine.
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Cold weather can also affect your breathing indirectly, through a seasonal increase in cold and influenza viruses. Both the common cold and flu can lead to increased mucus production, and that mucus can also make its way into the lungs, where it's known as phlegm, and cause coughing or worse lower respiratory symptoms.

More mucus and phlegm can cause breathing problems even among generally healthy people, and they can exacerbate asthma or other respiratory issues in others. In fact, three-quarters of those with asthma say cold and flu viruses can trigger their asthma symptoms.

Because cold weather leads us indoors and dampens some of our natural immune responses (like when it dries out our mucus), these viruses spread more freely during winter. This can make it hard to tell if the symptoms you have are just from breathing cold air or because you're coming down with something.

Generally, if the symptoms ease when you get out of the cold, they're probably a result of the cold air. If not, there may be something more going on -- and it may be time to visit the doctor. Note too that you should always contact your physician about any unexplained or unexpected shortness of breath.

How to get relief and stay healthy

Child wears a green scarf over mouth.
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If you're susceptible to breathing difficulties from asthma, COPD or other respiratory conditions, it's important to take extra precautions during the colder months. Here are a few strategies for keeping your lungs and airways as healthy as possible when the cold air strikes.

1. Breathe through your nose. Your nose warms and moistens cold air more effectively than your mouth, so breathing through your nose may help reduce discomfort from cold air.
2. Put a scarf over your nose and mouth. This traps some warmth from your breath and creates insulation against the cold air.
3. Stay hydrated. Dry air dehydrates you more quickly, so it's especially important to boost your fluid intake in winter. Staying hydrated will keep your mucus and phlegm moist so your nasal passages and lungs are better insulated against the cold.
4. Use a humidifier indoors. It's hard to fend off the dry outdoor air when your indoor air is already dry as a bone. Running an indoor humidifier will help you avoid drying up before you even set foot outside.
5. Make sure you keep your medicines in stock. If you take quick-relief medications for asthma or COPD, be sure you have them in stock and at the ready when you go out into the cold. Use your medications right away if you start to experience symptoms.
6. Monitor air quality. Air pollution can further aggravate symptoms in those with respiratory issues. Be sure to monitor the air quality forecast and stay indoors when pollution is high. 

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In most cases, colder air doesn't affect our breathing in any significant way. It typically means some mild discomfort, but nothing more. That's not true for everyone, though. If you have asthma, COPD or another respiratory condition, you may find that cold air exacerbates these issues. 

Keep in mind too that your health can change, and certain illnesses may make you more susceptible to respiratory difficulties. If you find breathing more difficult in winter, talk to your doctor and make sure you're well prepared to go outside.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.