Improved home ventilation that dehumidifies the air makes it easier for asthmatics to breathe at night.
Lowering indoor humidity is believed to lower the concentrations of moisture-loving dust mites - a major trigger for asthma-related breathing problems. To test this, researchers measured breathing patterns over 12 months in 119 men and women who were on average about 42 years old and had asthma for 9 to 30 years. Specialists retrofitted each home with a humidity-lowering ventilation system. They also steam-cleaned carpets, and replaced mattress covers and bedding, to clear dust mites.
In half the homes the ventilation systems actively exchanged indoor and outdoor air. In the other "control group", the systems had operational motors but non-operational fans to help ensure the groups remained "blinded" to what was actually happening.
There was overall difference in dust mite concentrations between the homes with and without a working ventilation system. Also, their comparison of morning breathing tests done at the start of the study and again at 3, 6, 9, and 12 months, showed no difference between those living with or without operational ventilation. However, participants living in homes with working ventilation systems showed an overall significant improvement in evening breathing tests, while those with non-working systems worsened in these tests.
The results may be due to the slightly reduced humidity, and ventilation may also have improved overall air quality resulting in improvement in asthma symptoms.
Lowering indoor humidity is believed to lower the concentrations of moisture-loving dust mites - a major trigger for asthma-related breathing problems. To test this, researchers measured breathing patterns over 12 months in 119 men and women who were on average about 42 years old and had asthma for 9 to 30 years. Specialists retrofitted each home with a humidity-lowering ventilation system. They also steam-cleaned carpets, and replaced mattress covers and bedding, to clear dust mites.
In half the homes the ventilation systems actively exchanged indoor and outdoor air. In the other "control group", the systems had operational motors but non-operational fans to help ensure the groups remained "blinded" to what was actually happening.
There was overall difference in dust mite concentrations between the homes with and without a working ventilation system. Also, their comparison of morning breathing tests done at the start of the study and again at 3, 6, 9, and 12 months, showed no difference between those living with or without operational ventilation. However, participants living in homes with working ventilation systems showed an overall significant improvement in evening breathing tests, while those with non-working systems worsened in these tests.
The results may be due to the slightly reduced humidity, and ventilation may also have improved overall air quality resulting in improvement in asthma symptoms.