Allergens, chemicals, and strong scents are common asthma triggers. But high humidity can be just as troublesome.
People with asthma have inflamed airways that are sensitive to things that may not bother other people. That’s why humidity, and all that comes with it, can cause symptoms in people with asthma.1
1. Humid air feels harder to breathe in. Some people believe moist air is heavier and harder to breathe. Heat and humidity usually occur together. When the air is harder to breathe, your body temperature can go up, causing you to sweat. This can lead to dehydration, which can make you breathe faster. All of these factors can trigger asthma symptoms.
Consider spending time outdoors in the mornings or evenings when heat and humidity levels tend to be lower. This can be especially important if you exercise outdoors.
2. Humidity may occur with extreme temperatures. Since humidity is usually highest in the summer, extreme heat can aggravate your airways, just like extreme cold air. Lungs of people with asthma tend to be more sensitive to extreme temperatures.2
Sudden changes in temperature can affect your lungs too. If you’ve ever left a dry, cold, air-conditioned building to go outside into hot, humid air, you know the change in air and temperature can be quite a shock. If you have asthma, the sudden change may cause an asthma attack.
3. Humidity can make air quality worse. Humid air alone is not all that triggers asthma symptoms. Humidity can increase levels of mold, dust mites, and ground-level ozone. All three are common asthma triggers.
Ozone, a gas that is a common air pollutant, irritates the airways. Ozone levels can rise along with humidity, triggering asthma symptoms.
Mold and dust mites thrive in humid weather. If you have allergic asthma and have allergies to mold and dust, you may have symptoms when counts increase. Mold can be found outside where leaves collect and in more tropical climates. An increase in indoor humidity can allow mold to grow in damp areas of your home, like bathrooms.
Dust mites are more of a concern inside when humidity is high. If the humidity in your home is higher than 50%, dust mites can multiply. Running your air conditioner, if you have one, or a dehumidifier can help you balance the humidity in your home.
You can’t always control your exposure to humidity, but there are many treatment options to help you manage asthma symptoms humidity may cause. See a board-certified allergist to help you come up with an asthma management plan.
Medical Review: July 2023 by Sarah Goff, MD, PhD
1. Hayes, D., Collins, P. B., Khosravi, M., Lin, R.-L., & Lee, L.-Y. (2012). Bronchoconstriction Triggered by Breathing Hot Humid Air in Patients with Asthma. American Journal of Respiratory and Critical Care Medicine, 185(11), 1190–1196. https://doi.org/10.1164/rccm.201201-0088oc
2. D’Amato, G., Vitale, C., De Martino, A., Viegi, G., Lanza, M., Molino, A., Sanduzzi, A., Vatrella, A., Annesi-Maesano, I., & D’Amato, M. (2015). Effects on asthma and respiratory allergy of Climate change and air pollution. Multidisciplinary Respiratory Medicine, 10(1). https://doi.org/10.1186/s40248-015-0036-x