Page last updated at 23:44 GMT, Sunday, 7 September 2008 00:44 UK

Sweaty people 'less asthma prone'

A new benefit from sweating?

The ability to sweat may do more than keep the body cool - it may mean a lower chance of exercise-related asthma, say scientists.

University of Michigan researchers say those who make less sweat, tears and saliva when exercising may have more breathing problems.

It is possible there is also too little fluid in their airways, they suggest.

However, asthma experts say it is too early to say whether the research will lead to practical patient benefits.

If athletes sweat, drool, or cry, at least they won't gasp
Dr Warren Lockette
University of Michigan

While the symptoms of "exercise-induced asthma" are similar to those of chronic asthma, people with the condition only develop attacks after several minutes of intense exercise.

It is a common condition among trained athletes but the reasons are poorly understood.

The US team looked at 56 volunteers suspected of having the condition, measuring their responses to a drug called pilocarpine, which induces sweat and saliva production, and another which constricts the airways in people with exercise-induced asthma.

Those who had the greatest response to the airway drug tended to have the lowest response to the sweating drug and vice versa.

Even without the help of the drug they also found a correlation in their volunteers between the amount they sweated and the amount of saliva and tear secretion.

Dry airway

While this did not prove that the mechanism behind lack of sweat was responsible, Dr Warren Lockette, who led the study, speculated that low sweating might also mean less fluid in the airways.

He said: "It now appears that how much fluid your airways secrete could be a key determinant in protecting you from exercise-induced asthma.

"So, if athletes sweat, drool, or cry, at least they won't gasp."

Leanne Male, from Asthma UK , said that the study was "interesting".

"It is the first time that a link has been proposed between sweating, saliva production and the likelihood of experiencing exercise-induced asthma.

"However, it is far too early however to say whether or not this research is important for people with asthma, as currently it has generated nothing more than an interesting hypothesis which has yet to be substantiated."


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