The effects of temperature and humidity on asthma

Both humidity and cold air are two very common asthma triggers and it is important that asthma sufferers bear this in mind.

Whilst exposing a child to cold air or a steamed room may help with some croup sufferers, this will not work for asthma. Both cold air and humidity, too high or too low, can actually trigger an asthma attack.

Studies show that a humidity level of 50% or greater may lead to increased incidence of asthma symptoms.

Two common theories for this are that:

• Humid air is heavier and harder to breathe
• Humid air may harbour fungi, moulds and dust mites that trigger asthma

Humid air is most often a problem in the summer months, especially in January and February.

Research has shown that air that is too dry can also trigger asthma. Air tends to be drier in the winter months.

Inhaling cold, dry air, can dry out the mucus membranes lining your lungs – which are your body’s natural defense mechanisms against viruses and bacteria – leading to increased asthma symptoms and infection.

75% of asthmatics have allergies. Dry mucus membranes may aggravate other allergy symptoms and it is therefore important to consider the temperature and humidity of your environment as low moisture levels in the air can trigger asthma symptoms.

Your nose humidifies inspired air, so if you breathe through your mouth, this air is not getting sufficiently humidified. This is especially important during the winter months when the air is drier. Studies have linked nasal congestion with severe asthma, as those with sinus trouble typically breathe through their mouths.

Exercise leads to rapid breathing and this results in more rapid drying out of the airway. This causes histamine to be released – causing inflammation of the air passages and the lungs, which may lead to bronchospasm. So, when doing exercise such as running, breathing in through the nose would be best.

The colder the air, the less humid the air is. This is why asthmatics, especially those with exercise-induced asthma, have trouble exercising outside when the air is cold. Rapid breathing of cold, dry air triggers asthma.

To prevent asthma, the Allergy Foundation of South Africa recommends that humidity be set between 35 and 50 percent. Humidifiers can be used in the winter months, and air conditioners and dehumidifiers in the summer months.

So, be aware that cold air, dry air, and humid air can trigger asthma.  A personalized approach to your daily habits and exercise preferences can allow you to live life to the fullest, while minimizing asthma attacks.