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High Dew Point and COPD: What You Should Know

Medically Reviewed by Michael W. Smith, MD on July 12, 2021

If you have a lung disorder, like chronic obstructive pulmonary disease (COPD), it’s important that you understand how the weather may affect your health. Experts know that humidity, or the amount of water vapor or moisture in the air, affects COPD. But dew point, or the temperature at which air moisture starts to stick to surfaces, might be a better measure of breathing comfort in those with the condition.

Dew Point and Breathing

Dew point is a tool that can tell how high humidity will be. It means the temperature that the air must be cooled down to in order to reach a relative humidity of 100%. Here, the air can’t hold any more water as vapor (its gaseous form). If it continues to cool down, water vapor will come out of the air as liquid, usually in the form of fog or rain.

The smaller the difference between the actual temperature and the dew point temperature, the higher the humidity will be. And if there’s a high dew point, there will be more water vapor molecules in the air.

If there’s more moisture in the air, less oxygen is present. While some people’s COPD symptoms get better in humid weather, less oxygen may make it harder for others to breathe.

If there’s a higher dew point and less available oxygen, people with lung conditions can develop bronchospasms. These happen when your airways contract and go into spasm. You might have a hard time breathing, start wheezing, or begin to cough.

Since COPD already affects your airways, lowered oxygen levels due to humidity can further worsen your symptoms.

We tend to feel the humid, sticky effects of a high dew point in the summer. But dew points can still be high in colder months. On clear and cold nights without much wind, frost or dew can form. You may not notice that the dew point is high, due to the lack of muggy weather, but a high dew point during cold weather can still harm your lungs. Air that’s cold and dry can irritate your airways if you have COPD. It may lead to wheezing, shortness of breath, or coughing.

How to Stay Prepared

If you know that humidity affects your COPD symptoms, it’s best to plan ahead to lessen flares.

Check the current dew point. You can check the dew point to see how the weather will feel. You can find it in your daily forecast information or search for it online.

Generally, most people find that dew points relate to comfort in this way:

  • Under 55 is pleasant
  • 56-60 is comfortable
  • 61-65 is slightly sticky
  • 66-70 is uncomfortable
  • 71-75 is oppressive
  • Higher than 76 is miserable

Plan to stay inside. If you know that the weather affects your COPD, don’t go outside when conditions aren’t suitable. Stay inside your home with a fan to keep you comfortable during humid days.

Protect your lungs in cold weather. If the weather is cold, cover your nose and mouth loosely with a scarf before you go outside. This will help warm the air before it goes into your lungs. Breathe in through your nose and out through your mouth.

Take prescribed medication. Always stick to your medication schedule to lower any COPD symptom flares. Doing so will help reduce the impact of any potential weather triggers.

Keep medication with you. In addition to routine drugs, keep quick-relief medications with you. If you feel that your COPD symptoms are worsening, use your relief medication as instructed.

WebMD Medical Reference

Sources

SOURCES:

Bronchiectasis and NTM Initiative: “Why Weather can Worsen your Lung Condition.”

San Francisco State University: “Concepts Related To Dew Point Temperature.”

National Health Service (U.K.): “COPD and the Weather.”

Fairview Health Services: “Bronchospasm (Adult).”

Mayo Clinic: “COPD.”

COPD Foundation: “Dew Point Comfort Scale.”

American Lung Association: “Weather and Your Lungs.”

National Weather Service: “Dew Point vs. Humidity.”

Iowa State University: “Dew and Plant Diseases.”

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