Respiratory Health

How Does Humidity Affect Asthma?

4 min read

By Apollo 24/7, Published on- 11 December 2020, Updated on - 12 April 2023

  • Share this article

  • 0

  • 1 like

Article Banner
Humidity causes difficulty in breathing especially for people with respiratory conditions like asthma. Humidity is the amount of water vapour or moisture in the air. Humidity levels are high when the weather is warm because air can hold more moisture at higher temperatures.
In hot and humid weather conditions, people with asthma, a chronic lung condition, should be vigilant about their asthma control. Humidity-related asthma symptoms can be prevented by taking medication, controlling indoor humidity levels, and avoiding exercising in humid conditions.

How humidity affects asthma

When exposed to high humidity, the inflamed airways in people with asthma are further swollen and produce more mucus. This makes it difficult to breathe. High levels of humidity can either trigger an asthma attack or worsen the symptoms.
  1. Breathing becomes harder

Humidity levels are the highest during the summer months as the moisture content in the air increases with a rise in temperature. With the increase in moisture, the air becomes heavier and denser. This irritates the airways making it harder to breathe. When breathing becomes harder, the body temperature increases producing sweat. Sweating in turn leads to dehydration making one breathe faster. The symptoms of asthma are triggered by a combination of these factors.
  1. Sensory nerve fibres in the airways get activated

When humid air is breathed in, there is an increase in airway temperature. This activates the airway sensory nerves called the C fibre nerves. Activation of the thermosensitive C fibres causes constriction or narrowing of the airways as a defensive response. These mechanisms lead to cough and make breathing more difficult in people with asthma.
  1. A suitable environment for asthma allergens

As humidity rises, there is an increase in the prevalence of airborne allergens. High humidity is a fertile environment for the growth of dust mites and molds, the two common triggers of allergic asthma. The dust mites thrive in humid air and are mostly found indoors in soft materials like mattresses, blankets, pillows, carpets, curtains, and upholstered furniture. Molds thrive in warm, humid, and dark areas indoors that contain a lot of moisture like the kitchen and bathrooms.
  1. Ozone levels are raised worsening air quality

High humidity is found to increase air pollution by increasing ground-level ozone. Ozone triggers asthma by causing irritation to the airways and the lungs. Asthma attacks are reported to significantly increase with the increase in the concentration of ozone. Humidity also makes the air stagnant that can trap pollutants such as car exhaust, and allergens like pollen and mold spores.
Asthma flare-ups triggered by extreme temperature and humidity conditions can be avoided by:
  • Staying indoors when the weather is hot and humid.
  • Use air conditioning to control heat and humidity indoors.
  • Keep track of the air quality and humidity levels both outside and indoors.
  • Maintain the recommended indoor humidity levels between 30% and 50%.
  • Keep windows, doors closed and curtains or blinds drawn. This keeps out the heat and allergens.
  • At night, consider opening the windows to let the cool air in only if the air pollution levels are low.
  • Avoid exercising outdoors when the weather is extremely hot and also avoid strenuous activity during these times.
  • Keep rescue medication handy and take medications as prescribed regularly.
  • Consider using a high-performance room air purifier that helps to breathe in pure air free of dust and allergic substances.
  • Drink plenty of water to replenish the fluids that are lost during hot and humid conditions to prevent dehydration.
  • Wear loose, light-coloured, cool clothes and a hat while going outdoors in hot weather.
  • Spend time outdoors in the mornings or evenings when heat and humidity levels are generally low.


Hot, humid weather conditions can be challenging for people with asthma. While one cannot control the weather, it is possible to reduce the exposure to humidity and avoid asthma symptoms during these times. Measures should be taken to keep the indoor humidity in the recommended range. When it is humid outside, people with asthma should consider staying indoors with the windows closed and air conditioning turned on.
For any questions relating to respiratory health, you can:

Talk to a Pulmonologist


Respiratory Health

Leave Comment


Email Id


  • Share this article

  • 0

  • 1 like