New research finds that very dry air can irritate the airways, while a salt-based aerosol may help
Extremely dry air can cause airway mucus to lose water and collapse onto tiny hair-like structures called cilia.
Researchers found that prolonged exposure to hot, dry conditions increased activity in genes linked to cough sensitivity.
A small clinical trial found that an alkaline magnesium salt aerosol reduced daily coughing compared with a placebo.
When the weather gets extremely hot and dry, staying hydrated may not be the only concern. New research from the University of North Carolina and collaborators suggests that very dry air can also affect the moisture lining the airways.
The airways are covered by a thin layer of mucus and tiny hair-like structures called cilia. Together, they help protect the respiratory system. But when the air is particularly dry, water can evaporate from this layer.
Researchers found that this can cause the mucus to thin and collapse onto the cilia, putting pressure on the cells underneath and making the airways more sensitive. The findings could help explain why extremely dry conditions may contribute to coughing and other respiratory symptoms.
How researchers studied the connection
The researchers used several approaches to investigate what happens to the airways in dry conditions.
First, they used mathematical modeling to examine how airway mucus responds to different levels of dryness and how various salt-based aerosols affect rehydration.
They also grew human bronchial airway cells in the laboratory and exposed them to either humid air or a hot, very dry environment. The dry-air condition was 35 degrees Celsius with 30% relative humidity. The researchers then examined changes in genes associated with cough sensitivity and the way airway cells respond to dehydration.
Finally, they conducted a randomized, double-blind, placebo-controlled clinical trial involving 10 people with refractory chronic cough in Riyadh, Saudi Arabia. Participants inhaled either an alkaline aerosol containing magnesium salts or a saline placebo.
What the study found and what it means
After eight hours in the hot, dry laboratory environment, the airway cells showed increased activity in several genes associated with cough hypersensitivity. The researchers also found that the magnesium salt aerosol could reverse the airway mucus collapse for several hours.
In the human trial, researchers reported that the magnesium salt aerosol reduced daily cough bouts by 59% compared with placebo after two weeks of treatment. The researchers also reported that the benefit continued after treatment ended.
Hypertonic salts have long been used to treat cystic fibrosis, a genetic condition of dehydrated airways, researcher Brian Button, Ph.D. said in a news release.
This study gives evidence that new kinds of hypertonic salts, longer acting and rendered therapeutic by optimization of rehydration processes within mucus we are only beginning to discover, might provide prophylaxis and treatment options for a human population previously spared the damages of mucosal dehydration.
There is an important caveat, however: The human portion of the study was very small, with only 10 participants, and the researchers say additional work is needed to understand the potential treatment.
For consumers, the findings offer a closer look at one way extreme dryness may affect the respiratory system. They also point to the possibility that rehydrating airway mucus could eventually become part of strategies for managing cough sensitivity, particularly in very dry environments.
Posted: 2026-09-29 16:55:57
