A variety of factors can trigger COPD flare-ups, including very high or very low humidity.

Chronic obstructive pulmonary disease (COPD) is a term for several conditions that damage the lungs and make breathing difficult. These issues tend to grow worse over time.

When symptoms suddenly become more pronounced, a person is experiencing a COPD flare-up.

If a person does not receive treatment, a flare-up can require hospitalization, and it may even be life-threatening.

Symptoms of a COPD flare-up can include:

  • more wheezing than usual
  • increased mucus production
  • persistent coughing
  • severe shortness of breath

In this article, we discuss the effects of humidity on COPD and how managing indoor humidity levels may prevent flare-ups. Also, we describe other COPD triggers and when to see a doctor.

A handprint on a glass full of moisture as humidity can effect COPDShare on Pinterest
Dominic Dähncke/Stocksy

Certain factors can trigger COPD flare-ups, including lung irritants, changes in weather, and infections.

Extremes in humidity can also cause COPD symptoms to worsen.

High humidity

High humidity levels may exacerbate symptoms for a variety of reasons. The body must work harder to breathe when humidity levels are high, especially when the air is hot.

Humid air is dense, due to the high water content. This density can increase airway resistance in the body. As a result, breathing may require more effort, which can worsen COPD symptoms, including shortness of breath and fatigue.

Humid, hot weather also requires the body to work harder to stay cool. Expending this energy requires more oxygen, which can contribute to feelings of breathlessness.

In a 2017 study, which included 82 people with COPD, researchers asked participants to record symptoms and indoor temperature and humidity levels every day for 18 months.

The results indicate that high humidity levels may contribute to exacerbated COPD symptoms.

Increased humidity may also encourage the growth of mold in the home or workplace, and mold is another common COPD trigger.

The disease causes the airways to become more sensitive. Common allergens, such as mold, can further irritate the lungs, prompting coughing, wheezing, and excess mucus production.

According to the United States Environmental Protection Agency (EPA), keeping indoor humidity levels below 60 percent can help prevent mold.

Low humidity

Very low humidity levels can also trigger or worsen symptoms of COPD. Dry air, especially if it is cold, can cause the airways to narrow, in an effect called a bronchospasm.

The following are some steps a person can take to reduce the effects of humidity on COPD symptoms:

Be aware of outdoor humidity levels

Local weather reports often include a humidity index. Some news outlets even issue a humidity advisory when conditions are extreme.

A combination of heat and high humidity can make breathing more difficult. The U.S. National Weather Service publish a heat index, which takes humidity levels into account and gives a sense of how uncomfortable the temperature may feel.

Limit outdoor activity when humidity is high

When the heat index is high, or the air feels very humid, it may be best to stay indoors as much as possible.

When humidity is very low, and the air is dry and cold, wearing a scarf over the mouth and nose can help warm the air before it enters the lungs.

Slow down

When humidity levels are extreme, it is essential for people with COPD to slow down and not overexert themselves.

Maintaining a gentle pace is always a good idea for a person with COPD, but is it especially important on hot and humid days. It can help, for example, to divide chores into smaller tasks and rest as needed.

Drink plenty of water

High temperatures and increased humidity levels cause the body to work harder, which results in more sweating and lost fluid. Avoid dehydration by keeping the body hydrated.

Control indoor humidity levels

It is often possible to control indoor humidity levels, particularly at home.

The EPA recommend keeping indoor humidity levels between 30 and 50 percent. A person can check levels using a small device called a humidistat.

To decrease indoor humidity:

  • Use an air conditioner or dehumidifier.
  • Open windows or use an extractor fan in moist areas, such as bathrooms and kitchens.
  • Repair any leaks or water damage.

High humidity levels are not the only COPD trigger. There several other factors can cause symptoms to flare up.

Although everyone is different, some common triggers include:

Extreme temperatures

When a person with COPD inhales hot air, it can increase airway inflammation and make breathing more difficult.

Breathing in cold air can cause a narrowing of the airways that may lead to increased wheezing and shortness of breath.

High pollen count

Allergies affect about 50 million people in the U.S. Hay fever is a common seasonal allergy that results from breathing in pollen.

Even in people with COPD who do not have hay fever, inhaling potential irritants, such as pollen, may worsen or trigger symptoms of COPD.

Outdoor air pollution

Outdoor air pollutants can include smoke, dust, and chemical fumes.

In a 2016 study involving 168 people with COPD, researchers found that even short-term exposure to air pollutants may increase the likelihood COPD flare-ups.


Respiratory infections, such as a cold or flu, can lead to an increase in COPD symptoms.

In people with the disease, these illnesses can further increase mucus production and inflammation in the airways, which can make breathing more challenging.

An increase in COPD symptoms can be serious and even potentially life-threatening. Consider seeing a doctor if symptoms include:

  • changes in mucus production, including color, amount, and consistency
  • more need for fast-acting inhalers
  • fever
  • shortness of breath that becomes worse or more frequent
  • unexplained fatigue
  • increased wheezing

A person may require emergency care if they experience:

  • severe shortness of breath
  • chest pain
  • blue lips or fingernails
  • confusion

Humidity, especially if it very high, can worsen COPD symptoms. Other common triggers include pollution, infection, and pollen.

A person can reduce indoor humidity by using an air conditioner or dehumidifier. Checking local weather reports can help determine when conditions are suitable.

Recognizing and treating a COPD flare-up, possibly with medical aid, can prevent symptoms from becoming life-threatening.