Are Hot Showers Bad For Asthma?

The reason that your hot shower may be triggering your asthma is due to a class of contaminants in your water called Volatile Organic Compounds(VOCs). In fact, if this is the case, even a cold shower will leave you breathless.

Firstly, all asthma patients do not have the same triggers. For instance, some asthmatics might find difficulty breathing in hot and humid conditions, while others get triggered by cold and dry conditions.

Or maybe both.

For some asthmatics, the steam from hot showers helps open up airways and loosen up the mucus lining. However, others find themselves unable to breathe within minutes of stepping into a hot shower.

Why could this be? All my research into this pointed to just one fact- that there haven’t been enough scientific studies on this topic, and we need to know more. So, while there is a general list of environmental conditions which might trigger an attack, what isn’t clearly known is why everyone’s triggers are not exactly the same.

So, while the triggers related to air quality can’t be generalised, there is a major contaminant that, through several studies such as this one, has been seen to cause breathing problems like asthma, or worsen existing breathing problems.

Volatile Organic Compounds, by definition are volatile. Hence, they evaporate easily, even at normal temperatures, and can cause respiratory problems when inhaled.

There are two ways through which VOCs get into your water:

  • Due to chlorine/chloramines
  • External contamination due to human activity

The Chlorine/Chloramine Effect

VOCs are formed in water due to a reaction between chlorine/chloramines in water and organic compounds(compounds that contain carbon). One of the most common VOCs is chloroform- which was used as anesthesia until it was banned in 1976 for having cancerous properties.

Now, water chlorination is a common practice worldwide when it comes to public water purification. In some areas, chloramination(chlorine + ammonia) has replaced chlorination, but nonetheless, it has the same effect of acting as an oxidizing agent that form VOCs in water.

When the chlorine/chloramine in water combines with organic matter in water, it forms these volatile organic compounds, such as chloroform, which are easily evaporated during the time we shower.

Further, when inhaled, VOCs can cause coughing and wheezing even for those with normal respiratory systems. For asthmatics, inhalation of VOCs can be even more severe.

Apart from forming VOCs, chlorine/chloramine in water can have a lot of harmful effects on the human body, such as hair fall, rashes, dry scalp and skin, acne, etc. Read more about that in this post- 7 Proven Chloramine Vs Chlorine Water Treatment Methods

External Human Contamination:

VOCs are generally not found in surface water, such as rivers, lakes or streams, as they evaporate over time. The USEPA, however, estimates that over 1/5th of the US water supply contains VOCs. According to Minnesota Health Department:

Most VOCs found in the environment result from human activity. When VOCs are spilled or improperly disposed of, a portion will evaporate, but some will soak into the ground. In soil, VOCs may be carried deeper by rain, water or snow melt and eventually reach the groundwater table. When VOCs migrate underground to nearby wells, they can eventually end up in drinking water supplies.

If you’re unsure, the best way to know is get your water supply tested for VOCs by a local laboratory. If you live in the US, you could also get access to your water supplier’s annual water quality report.

Common Effects On Humans Due To VOCs

According to EPA, these are:

  • Eye, nose and throat irritation
  • Headaches, loss of coordination and nausea
  • Damage to liver, kidney and central nervous system
  • Some organics can cause cancer in animals, some are suspected or known to cause cancer in humans.

How To Test For VOC Levels at Home

Get an air quality tester, such as this one on Amazon. If you’re looking for something a little more good looking that you could display on a coffee table, say, you could go for this product on Amazon.

I highly recommend getting an air quality tester because it is a relatively inexpensive way of finding out the VOC contamination levels, as well as other common air pollutants in your home. Otherwise, getting your air quality tested by a lab, such as through this Amazon product, may cost you about 100-150$ extra.

Prevent Asthma Attacks From Showers: Get A Shower Filter

I recommend you get a shower filter for removing VOCs from your water. Keep in mind that there are two shower filter technologies commonly used:

  • KDF(Kinetic Degradation Fluxion) Shower Filters
  • Vitamin C Shower Filters

Vitamin C filters are good at removing chlorine and chloramines, but not much else. Instead, get a KDF shower filter, which removes VOCs, chlorine, heavy metals and other common contaminants in water.

The added advantage of KDF shower filters is that they are way cheaper than Vitamin C filters. They are usually priced between 15-50$, such as this one on Amazon.

Additionally, I’d also recommend installing and using an exhaust fan, to limit the steam in the bathroom and keep it well ventilated.

Other Sources of VOCs at home

According to the EPA’s indoor air quality report, some common sources of VOC indoors are:

  • paints, paint strippers and other solvents
  • wood preservatives
  • aerosol sprays
  • cleansers and disinfectants
  • moth repellents and air fresheners
  • stored fuels and automotive products
  • hobby supplies
  • dry-cleaned clothing
  • pesticide

Sounds like a lot, right? While the levels of VOCs indoors may usually not be very high, asthmatics or people suffering from other respiratory diseases are more sensitive, and are affected easily.

Here are a few things you can do to reduce VOC levels at home:

  • Do not allow new furnishings into the home for a week or so. Let them de-gas in the garage first.
  • Do not sleep in freshly painted rooms. Open windows to allow for ventilation for a few days till the emissions from the paint subside.
  • Buy limited quantities of chemicals like paint- only as much as you need, so that you don’t need to store them
  • Added Tip: Latex paints contain lesser VOCs than oil paints
  • Go for alternative pest control methods that don’t use pesticides


Ultimately, it is tough to get rid of VOCs because they have so many sources and not many of them can be easily detected as they have no smell. Even though there are no guidelines for airborne VOC levels in residential homes, if you are affected by them, it is best to minimize VOCs as much as possible.

Here’s my final recommendation:

  • Buy an air purifier- Will remove VOCs from air, along with other pollutants such as dust that irritate the airways. Ensure that it has a HEPA filter for removing VOCs, like this popular one on Amazon.
  • Get a shower filter to safeguard yourself against VOC emissions in the bathroom. Ensure that you buy a KDF shower filter, like this bestseller on Amazon.Also install an exhaust fan to keep the bathroom well ventilated.


Recent Content