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. 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 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. 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."