Sweating linked to exercise-induced asthma

Active people who are prone to sweating may have some built-in protection from exercise-induced asthma attacks, a new study suggests.

The unusual connection suggests that the same mechanisms responsible for generating a person's sweat "volume" also determines the amount of water secreted by the airways, the researchers speculate.

Essentially, they say, people who sweat less may also have drier airways, which could make the airways more likely to constrict and cause breathing problems during exercise.

The findings, published in the medical journal Chest, are based on tests of 56 healthy Marines who had symptoms of exercise-induced asthma - wheezing, breathless or coughing in response to physical exertion.

How the study was conducted
Researchers at the Naval Medical Centre in San Diego measured the volunteers' lung function before and after giving them a medication called methacholine, which, in someone with asthma, causes the airways to constrict at low doses.

The researchers also gave the study participants a drug called pilocarpine, which induces sweat and saliva production.

They found that volunteers who tended to sweat the most in response to the drug were less likely to show airway constriction after being given methacholine. Heavy sweaters also tended to have greater saliva and tear production.

The findings do not prove that a tendency toward sweating helps shield active people from exercise-induced asthma, according to Dr Warren Lockette, the senior researcher on the study.

A common mechanism
However, he explained in a statement, the results are consistent with the idea that a common mechanism may underlie diminished sweat production and reduced water secretion in the airways.

"It now appears that how much fluid your airways secrete could be a key determinant in protecting you from exercise-induced asthma," he said. "So, if athletes sweat, drool, or cry, at least they won't gasp." – (Reuters Health)

SOURCE: Chest, September 2008.