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Are dehumidifiers good for asthma?
Are dehumidifiers good for asthma or is it just another urban myth?
Asthma is a frustrating, chronic condition in which a person's airways narrow and swell, according to the Mayo Clinic. This can cause shortness of breath, chest tightness or pain, wheezing or difficulty breathing.
Asthma is incurable, however, doctors can help patients manage the condition through education about the common triggers, advice on possible lifestyle changes and medication.
One of these triggers is high humidity. According to the Asthma and Allergy Foundation of America, high temperatures and thicker air can negatively affect breathing which, in turn, can lead to lung irritation and breathing problems.
So if dry air is exacerbating symptoms, are dehumidifiers good for asthma? Currently, there is not enough evidence to recommend them as a tool for managing asthma specifically, however, experts told Live Science that in some instances they may be useful.
Is a dehumidifier good for asthma?
Dehumidifiers are devices that use a fan to suck excess moisture out of the air and release drier air back into the room, thereby reducing humidity levels.
Dr. Jessica Shepherd, the chief medical officer at Verywell Health, told Live Science that dehumidifiers are not recommended as a tool to manage asthma specifically, but in certain cases they can be useful.
"Dehumidifiers should not be used to manage asthma, however, yes, they can ease asthma symptoms," she said. However, the appliance is only useful if high humidity is a factor that is aggravating a person's asthma, she said.
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"Heat and humidity create changes in the air which will increase the demand for oxygen," Shepherd said. "It is also important to monitor the humidity level, especially in the home, with a hygrometer as humidity levels that are over 45% encourage mold, bacteria, and dust mites growth — all of which are common asthma triggers."
So far, scientific evidence on the benefits of dehumidifiers for asthma is lacking. A 2013 review of studies looking at the effects of mechanical dehumidifiers on asthmatic patients, published in the Cochrane Database of Systematic Reviews, found that the appliances had no significant benefits.
There could be a reason why dehumidifiers aren't considered a standard tool for managing asthma — dry air can also aggravate the lungs. So, to avoid doing more harm than good, dehumidifiers should only be used when the air is extremely damp. According to the Environmental Protection Agency, ideal humidity in a home is between 30% to 50%.
Is humidity or dryness best for asthmatics?
Many doctors avoid recommending dehumidifiers to asthmatic patients, simply because they can make the air excessively dry if used at the wrong time of year or in the wrong circumstances.
Dr. David Edwards, an aerosol scientist, and faculty member at Harvard University, told Live Science that while humid air can be bad for asthmatics, dry air can actually be worse.
"At low humidity, the upper airways, which necessarily hydrate inhaled air, can dry out, slowing cilia beat frequency that is critical for clearing inhaled debris, and stressing cells," he said. "Low humidity also promotes breakup of mucus into respiratory droplets, which can carry inhaled contaminants deeper into the airways where they can promote respiratory illness including bronchoconstriction."
Edwards pointed to a peer-reviewed 1977 study in the Journal of Allergy and Clinical Immunology that found that exercise-induced asthma (EIA) occurs more frequently in dry air than in humid air. The study even noted that, "High humidity of inspired air could be the reason why EIA is less prevalent in swimming, as compared with other modes of exercise." In other words, it's more important to avoid dryness than humidity as an asthmatic.
So, it's best to avoid using a dehumidifier in the home unless there's absolutely certainty that the internal humidity levels are above optimal levels. While dry air may be worse for asthma than humid air, both come with their challenges.
"It is very important to maintain a moderate humidity in the control of an air space — whether by dehumidifying a very wet room or humidifying a very dry room," Edwards said.
What are other methods for managing humidity-induced asthma?
While dehumidifiers may help to ease humidity-induced asthma symptoms, they will always work best alongside other medically approved methods for asthma management. Shepherd said these include:
- Reducing exposure to allergens or irritants that trigger asthma
- Getting an annual flu shot
- Weight management
- Limiting exposure to any allergens including pollen, dust, mold and pet dander
- Avoiding smoking cigarettes or vaping
- Breathing exercises
Asthma is a complicated chronic condition and managing symptoms requires a careful plan, as well as experience of a person's unique environmental triggers. While dry air is known to aggravate asthma, excessive levels of humidity in a home can also lead to irritation or an asthma attack. If you think your symptoms may be related to high humidity, make sure to consult a doctor.
This article is for informational purposes only and is not meant to offer medical advice.
Meg Walters is a freelance journalist and features writer. Raised in Canada and based in South East London, Meg covers culture, entertainment, lifestyle, and health. Her work has appeared in Cosmopolitan, i-D, Refinery29, Stylist, GQ, Shondaland, Healthline, HelloGiggles and other publications.
When she's not writing, Meg is probably daydreaming about traveling the world, re-watching an old rom-com with a glass of wine, or wasting time on Twitter, where you can follow her @wordsbymeg.