Dry airways become irritated and swollen, which worsens asthma symptoms. Cold air also causes your airways to produce a substance called histamine, which is the same chemical your body makes during an allergy attack. Histamine triggers wheezing and other asthma symptoms.

When you work out, your body needs more oxygen, so your breathing speeds up. Often, you’ll breathe through your mouth to take in more air. While your nose has blood vessels that warm and humidify the air before it reaches your lungs, air that travels directly through your mouth remains cold and dry. This is just one way that exercising outdoors in cold weather increases your likelihood of having an asthma attack.
Colds, flu, and other respiratory infections tend to circulate during the winter months. These infections are also known to set off asthma symptoms.
Cold air can also drive you indoors, where dust, mold, and pet dander flourish. These allergens set off asthma symptoms in some people.

Make sure your asthma is under control before winter arrives. See your doctor to develop an asthma action plan, and then take the medicines your doctor prescribed. You may take medicine every day or just when you need it.
Long-term controller medicines are drugs you take every day to manage your asthma symptoms. They include inhaled corticosteroids, long-acting beta-agonists, and leukotriene modifiers.
Quick-relief medicines are medicines that you only take when you need them, such as before exercising in the cold. Short-acting bronchodilators and anticholinergics are examples of these drugs.

Here are a few tips:

  • Drink extra fluids in the winter. This can keep the mucus in your lungs thinner and easier for your body to remove.
  • Try to avoid anyone who appears to be sick.
  • Get your flu vaccine early in the fall.
  • Vacuum and dust your home often to remove indoor allergens.
  • Wash your sheets and blankets every week in hot water to get rid of dust mites.